var ZLMRTCClient = (function (exports) {
    'use strict';

    const Events$1 = {
        WEBRTC_NOT_SUPPORT: 'WEBRTC_NOT_SUPPORT',
        WEBRTC_ICE_CANDIDATE_ERROR: 'WEBRTC_ICE_CANDIDATE_ERROR',
        WEBRTC_OFFER_ANWSER_EXCHANGE_FAILED: 'WEBRTC_OFFER_ANWSER_EXCHANGE_FAILED',
        WEBRTC_ON_REMOTE_STREAMS: 'WEBRTC_ON_REMOTE_STREAMS',
        WEBRTC_ON_LOCAL_STREAM: 'WEBRTC_ON_LOCAL_STREAM',
        WEBRTC_ON_CONNECTION_STATE_CHANGE: 'WEBRTC_ON_CONNECTION_STATE_CHANGE',
        WEBRTC_ON_DATA_CHANNEL_OPEN: 'WEBRTC_ON_DATA_CHANNEL_OPEN',
        WEBRTC_ON_DATA_CHANNEL_CLOSE: 'WEBRTC_ON_DATA_CHANNEL_CLOSE',
        WEBRTC_ON_DATA_CHANNEL_ERR: 'WEBRTC_ON_DATA_CHANNEL_ERR',
        WEBRTC_ON_DATA_CHANNEL_MSG: 'WEBRTC_ON_DATA_CHANNEL_MSG',
        CAPTURE_STREAM_FAILED: 'CAPTURE_STREAM_FAILED'
    };

    const VERSION$1 = '1.0.1';
    const BUILD_DATE = 'Mon Mar 27 2023 19:11:59 GMT+0800 (China Standard Time)';

    // Copyright (C) <2018> Intel Corporation
    //
    // SPDX-License-Identifier: Apache-2.0

    // eslint-disable-next-line require-jsdoc
    function isFirefox() {
        return window.navigator.userAgent.match('Firefox') !== null;
    }

    // eslint-disable-next-line require-jsdoc
    function isChrome() {
        return window.navigator.userAgent.match('Chrome') !== null;
    }

    // eslint-disable-next-line require-jsdoc
    function isEdge() {
        return window.navigator.userAgent.match(/Edge\/(\d+).(\d+)$/) !== null;
    }

    // Copyright (C) <2018> Intel Corporation

    /**
     * @class AudioSourceInfo
     * @classDesc Source info about an audio track. Values: 'mic', 'screen-cast', 'file', 'mixed'.
     * @memberOf Owt.Base
     * @readonly
     * @enum {string}
     */
    const AudioSourceInfo = {
        MIC: 'mic',
        SCREENCAST: 'screen-cast',
        FILE: 'file',
        MIXED: 'mixed'
    };

    /**
     * @class VideoSourceInfo
     * @classDesc Source info about a video track. Values: 'camera', 'screen-cast', 'file', 'mixed'.
     * @memberOf Owt.Base
     * @readonly
     * @enum {string}
     */
    const VideoSourceInfo = {
        CAMERA: 'camera',
        SCREENCAST: 'screen-cast',
        FILE: 'file',
        MIXED: 'mixed'
    };

    /**
     * @class TrackKind
     * @classDesc Kind of a track. Values: 'audio' for audio track, 'video' for video track, 'av' for both audio and video tracks.
     * @memberOf Owt.Base
     * @readonly
     * @enum {string}
     */
    const TrackKind = {
        /**
         * Audio tracks.
         * @type string
         */
        AUDIO: 'audio',
        /**
         * Video tracks.
         * @type string
         */
        VIDEO: 'video',
        /**
         * Both audio and video tracks.
         * @type string
         */
        AUDIO_AND_VIDEO: 'av'
    };

    /**
     * @class Resolution
     * @memberOf Owt.Base
     * @classDesc The Resolution defines the size of a rectangle.
     * @constructor
     * @param {number} width
     * @param {number} height
     */
    class Resolution {
        // eslint-disable-next-line require-jsdoc
        constructor(width, height) {
            /**
             * @member {number} width
             * @instance
             * @memberof Owt.Base.Resolution
             */
            this.width = width;
            /**
             * @member {number} height
             * @instance
             * @memberof Owt.Base.Resolution
             */
            this.height = height;
        }
    }

    /*
	 *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
	 *
	 *  Use of this source code is governed by a BSD-style license
	 *  that can be found in the LICENSE file in the root of the source
	 *  tree.
	 */

    let logDisabled_ = true;
    let deprecationWarnings_ = true;

    /**
     * Extract browser version out of the provided user agent string.
     *
     * @param {!string} uastring userAgent string.
     * @param {!string} expr Regular expression used as match criteria.
     * @param {!number} pos position in the version string to be returned.
     * @return {!number} browser version.
     */
    function extractVersion(uastring, expr, pos) {
        const match = uastring.match(expr);
        return match && match.length >= pos && parseInt(match[pos], 10);
    }

    // Wraps the peerconnection event eventNameToWrap in a function
    // which returns the modified event object (or false to prevent
    // the event).
    function wrapPeerConnectionEvent(window, eventNameToWrap, wrapper) {
        if (!window.RTCPeerConnection) {
            return;
        }
        const proto = window.RTCPeerConnection.prototype;
        const nativeAddEventListener = proto.addEventListener;
        proto.addEventListener = function (nativeEventName, cb) {
            if (nativeEventName !== eventNameToWrap) {
                return nativeAddEventListener.apply(this, arguments);
            }
            const wrappedCallback = (e) => {
                const modifiedEvent = wrapper(e);
                if (modifiedEvent) {
                    if (cb.handleEvent) {
                        cb.handleEvent(modifiedEvent);
                    } else {
                        cb(modifiedEvent);
                    }
                }
            };
            this._eventMap = this._eventMap || {};
            if (!this._eventMap[eventNameToWrap]) {
                this._eventMap[eventNameToWrap] = new Map();
            }
            this._eventMap[eventNameToWrap].set(cb, wrappedCallback);
            return nativeAddEventListener.apply(this, [nativeEventName,
                wrappedCallback]);
        };

        const nativeRemoveEventListener = proto.removeEventListener;
        proto.removeEventListener = function (nativeEventName, cb) {
            if (nativeEventName !== eventNameToWrap || !this._eventMap
                || !this._eventMap[eventNameToWrap]) {
                return nativeRemoveEventListener.apply(this, arguments);
            }
            if (!this._eventMap[eventNameToWrap].has(cb)) {
                return nativeRemoveEventListener.apply(this, arguments);
            }
            const unwrappedCb = this._eventMap[eventNameToWrap].get(cb);
            this._eventMap[eventNameToWrap].delete(cb);
            if (this._eventMap[eventNameToWrap].size === 0) {
                delete this._eventMap[eventNameToWrap];
            }
            if (Object.keys(this._eventMap).length === 0) {
                delete this._eventMap;
            }
            return nativeRemoveEventListener.apply(this, [nativeEventName,
                unwrappedCb]);
        };

        Object.defineProperty(proto, 'on' + eventNameToWrap, {
            get() {
                return this['_on' + eventNameToWrap];
            },
            set(cb) {
                if (this['_on' + eventNameToWrap]) {
                    this.removeEventListener(eventNameToWrap,
                        this['_on' + eventNameToWrap]);
                    delete this['_on' + eventNameToWrap];
                }
                if (cb) {
                    this.addEventListener(eventNameToWrap,
                        this['_on' + eventNameToWrap] = cb);
                }
            },
            enumerable: true,
            configurable: true
        });
    }

    function disableLog(bool) {
        if (typeof bool !== 'boolean') {
            return new Error('Argument type: ' + typeof bool +
                '. Please use a boolean.');
        }
        logDisabled_ = bool;
        return (bool) ? 'adapter.js logging disabled' :
            'adapter.js logging enabled';
    }

    /**
     * Disable or enable deprecation warnings
     * @param {!boolean} bool set to true to disable warnings.
     */
    function disableWarnings(bool) {
        if (typeof bool !== 'boolean') {
            return new Error('Argument type: ' + typeof bool +
                '. Please use a boolean.');
        }
        deprecationWarnings_ = !bool;
        return 'adapter.js deprecation warnings ' + (bool ? 'disabled' : 'enabled');
    }

    function log$1() {
        if (typeof window === 'object') {
            if (logDisabled_) {
                return;
            }
            if (typeof console !== 'undefined' && typeof console.log === 'function') {
                console.log.apply(console, arguments);
            }
        }
    }

    /**
     * Shows a deprecation warning suggesting the modern and spec-compatible API.
     */
    function deprecated(oldMethod, newMethod) {
        if (!deprecationWarnings_) {
            return;
        }
        console.warn(oldMethod + ' is deprecated, please use ' + newMethod +
            ' instead.');
    }

    /**
     * Browser detector.
     *
     * @return {object} result containing browser and version
     *     properties.
     */
    function detectBrowser(window) {
        // Returned result object.
        const result = {browser: null, version: null};

        // Fail early if it's not a browser
        if (typeof window === 'undefined' || !window.navigator) {
            result.browser = 'Not a browser.';
            return result;
        }

        const {navigator} = window;

        if (navigator.mozGetUserMedia) { // Firefox.
            result.browser = 'firefox';
            result.version = extractVersion(navigator.userAgent,
                /Firefox\/(\d+)\./, 1);
        } else if (navigator.webkitGetUserMedia ||
            (window.isSecureContext === false && window.webkitRTCPeerConnection &&
                !window.RTCIceGatherer)) {
            // Chrome, Chromium, Webview, Opera.
            // Version matches Chrome/WebRTC version.
            // Chrome 74 removed webkitGetUserMedia on http as well so we need the
            // more complicated fallback to webkitRTCPeerConnection.
            result.browser = 'chrome';
            result.version = extractVersion(navigator.userAgent,
                /Chrom(e|ium)\/(\d+)\./, 2);
        } else if (navigator.mediaDevices &&
            navigator.userAgent.match(/Edge\/(\d+).(\d+)$/)) { // Edge.
            result.browser = 'edge';
            result.version = extractVersion(navigator.userAgent,
                /Edge\/(\d+).(\d+)$/, 2);
        } else if (window.RTCPeerConnection &&
            navigator.userAgent.match(/AppleWebKit\/(\d+)\./)) { // Safari.
            result.browser = 'safari';
            result.version = extractVersion(navigator.userAgent,
                /AppleWebKit\/(\d+)\./, 1);
            result.supportsUnifiedPlan = window.RTCRtpTransceiver &&
                'currentDirection' in window.RTCRtpTransceiver.prototype;
        } else { // Default fallthrough: not supported.
            result.browser = 'Not a supported browser.';
            return result;
        }

        return result;
    }

    /**
     * Checks if something is an object.
     *
     * @param {*} val The something you want to check.
     * @return true if val is an object, false otherwise.
     */
    function isObject$1(val) {
        return Object.prototype.toString.call(val) === '[object Object]';
    }

    /**
     * Remove all empty objects and undefined values
     * from a nested object -- an enhanced and vanilla version
     * of Lodash's `compact`.
     */
    function compactObject(data) {
        if (!isObject$1(data)) {
            return data;
        }

        return Object.keys(data).reduce(function (accumulator, key) {
            const isObj = isObject$1(data[key]);
            const value = isObj ? compactObject(data[key]) : data[key];
            const isEmptyObject = isObj && !Object.keys(value).length;
            if (value === undefined || isEmptyObject) {
                return accumulator;
            }
            return Object.assign(accumulator, {[key]: value});
        }, {});
    }

    /* iterates the stats graph recursively. */
    function walkStats(stats, base, resultSet) {
        if (!base || resultSet.has(base.id)) {
            return;
        }
        resultSet.set(base.id, base);
        Object.keys(base).forEach(name => {
            if (name.endsWith('Id')) {
                walkStats(stats, stats.get(base[name]), resultSet);
            } else if (name.endsWith('Ids')) {
                base[name].forEach(id => {
                    walkStats(stats, stats.get(id), resultSet);
                });
            }
        });
    }

    /* filter getStats for a sender/receiver track. */
    function filterStats(result, track, outbound) {
        const streamStatsType = outbound ? 'outbound-rtp' : 'inbound-rtp';
        const filteredResult = new Map();
        if (track === null) {
            return filteredResult;
        }
        const trackStats = [];
        result.forEach(value => {
            if (value.type === 'track' &&
                value.trackIdentifier === track.id) {
                trackStats.push(value);
            }
        });
        trackStats.forEach(trackStat => {
            result.forEach(stats => {
                if (stats.type === streamStatsType && stats.trackId === trackStat.id) {
                    walkStats(result, stats, filteredResult);
                }
            });
        });
        return filteredResult;
    }

    /*
	 *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
	 *
	 *  Use of this source code is governed by a BSD-style license
	 *  that can be found in the LICENSE file in the root of the source
	 *  tree.
	 */
    const logging = log$1;

    function shimGetUserMedia$3(window, browserDetails) {
        const navigator = window && window.navigator;

        if (!navigator.mediaDevices) {
            return;
        }

        const constraintsToChrome_ = function (c) {
            if (typeof c !== 'object' || c.mandatory || c.optional) {
                return c;
            }
            const cc = {};
            Object.keys(c).forEach(key => {
                if (key === 'require' || key === 'advanced' || key === 'mediaSource') {
                    return;
                }
                const r = (typeof c[key] === 'object') ? c[key] : {ideal: c[key]};
                if (r.exact !== undefined && typeof r.exact === 'number') {
                    r.min = r.max = r.exact;
                }
                const oldname_ = function (prefix, name) {
                    if (prefix) {
                        return prefix + name.charAt(0).toUpperCase() + name.slice(1);
                    }
                    return (name === 'deviceId') ? 'sourceId' : name;
                };
                if (r.ideal !== undefined) {
                    cc.optional = cc.optional || [];
                    let oc = {};
                    if (typeof r.ideal === 'number') {
                        oc[oldname_('min', key)] = r.ideal;
                        cc.optional.push(oc);
                        oc = {};
                        oc[oldname_('max', key)] = r.ideal;
                        cc.optional.push(oc);
                    } else {
                        oc[oldname_('', key)] = r.ideal;
                        cc.optional.push(oc);
                    }
                }
                if (r.exact !== undefined && typeof r.exact !== 'number') {
                    cc.mandatory = cc.mandatory || {};
                    cc.mandatory[oldname_('', key)] = r.exact;
                } else {
                    ['min', 'max'].forEach(mix => {
                        if (r[mix] !== undefined) {
                            cc.mandatory = cc.mandatory || {};
                            cc.mandatory[oldname_(mix, key)] = r[mix];
                        }
                    });
                }
            });
            if (c.advanced) {
                cc.optional = (cc.optional || []).concat(c.advanced);
            }
            return cc;
        };

        const shimConstraints_ = function (constraints, func) {
            if (browserDetails.version >= 61) {
                return func(constraints);
            }
            constraints = JSON.parse(JSON.stringify(constraints));
            if (constraints && typeof constraints.audio === 'object') {
                const remap = function (obj, a, b) {
                    if (a in obj && !(b in obj)) {
                        obj[b] = obj[a];
                        delete obj[a];
                    }
                };
                constraints = JSON.parse(JSON.stringify(constraints));
                remap(constraints.audio, 'autoGainControl', 'googAutoGainControl');
                remap(constraints.audio, 'noiseSuppression', 'googNoiseSuppression');
                constraints.audio = constraintsToChrome_(constraints.audio);
            }
            if (constraints && typeof constraints.video === 'object') {
                // Shim facingMode for mobile & surface pro.
                let face = constraints.video.facingMode;
                face = face && ((typeof face === 'object') ? face : {ideal: face});
                const getSupportedFacingModeLies = browserDetails.version < 66;

                if ((face && (face.exact === 'user' || face.exact === 'environment' ||
                        face.ideal === 'user' || face.ideal === 'environment')) &&
                    !(navigator.mediaDevices.getSupportedConstraints &&
                        navigator.mediaDevices.getSupportedConstraints().facingMode &&
                        !getSupportedFacingModeLies)) {
                    delete constraints.video.facingMode;
                    let matches;
                    if (face.exact === 'environment' || face.ideal === 'environment') {
                        matches = ['back', 'rear'];
                    } else if (face.exact === 'user' || face.ideal === 'user') {
                        matches = ['front'];
                    }
                    if (matches) {
                        // Look for matches in label, or use last cam for back (typical).
                        return navigator.mediaDevices.enumerateDevices()
                            .then(devices => {
                                devices = devices.filter(d => d.kind === 'videoinput');
                                let dev = devices.find(d => matches.some(match =>
                                    d.label.toLowerCase().includes(match)));
                                if (!dev && devices.length && matches.includes('back')) {
                                    dev = devices[devices.length - 1]; // more likely the back cam
                                }
                                if (dev) {
                                    constraints.video.deviceId = face.exact ? {exact: dev.deviceId} :
                                        {ideal: dev.deviceId};
                                }
                                constraints.video = constraintsToChrome_(constraints.video);
                                logging('chrome: ' + JSON.stringify(constraints));
                                return func(constraints);
                            });
                    }
                }
                constraints.video = constraintsToChrome_(constraints.video);
            }
            logging('chrome: ' + JSON.stringify(constraints));
            return func(constraints);
        };

        const shimError_ = function (e) {
            if (browserDetails.version >= 64) {
                return e;
            }
            return {
                name: {
                    PermissionDeniedError: 'NotAllowedError',
                    PermissionDismissedError: 'NotAllowedError',
                    InvalidStateError: 'NotAllowedError',
                    DevicesNotFoundError: 'NotFoundError',
                    ConstraintNotSatisfiedError: 'OverconstrainedError',
                    TrackStartError: 'NotReadableError',
                    MediaDeviceFailedDueToShutdown: 'NotAllowedError',
                    MediaDeviceKillSwitchOn: 'NotAllowedError',
                    TabCaptureError: 'AbortError',
                    ScreenCaptureError: 'AbortError',
                    DeviceCaptureError: 'AbortError'
                }[e.name] || e.name,
                message: e.message,
                constraint: e.constraint || e.constraintName,
                toString() {
                    return this.name + (this.message && ': ') + this.message;
                }
            };
        };

        const getUserMedia_ = function (constraints, onSuccess, onError) {
            shimConstraints_(constraints, c => {
                navigator.webkitGetUserMedia(c, onSuccess, e => {
                    if (onError) {
                        onError(shimError_(e));
                    }
                });
            });
        };
        navigator.getUserMedia = getUserMedia_.bind(navigator);

        // Even though Chrome 45 has navigator.mediaDevices and a getUserMedia
        // function which returns a Promise, it does not accept spec-style
        // constraints.
        if (navigator.mediaDevices.getUserMedia) {
            const origGetUserMedia = navigator.mediaDevices.getUserMedia.bind(navigator.mediaDevices);
            navigator.mediaDevices.getUserMedia = function (cs) {
                return shimConstraints_(cs, c => origGetUserMedia(c).then(stream => {
                    if (c.audio && !stream.getAudioTracks().length ||
                        c.video && !stream.getVideoTracks().length) {
                        stream.getTracks().forEach(track => {
                            track.stop();
                        });
                        throw new DOMException('', 'NotFoundError');
                    }
                    return stream;
                }, e => Promise.reject(shimError_(e))));
            };
        }
    }

    /*
	 *  Copyright (c) 2018 The adapter.js project authors. All Rights Reserved.
	 *
	 *  Use of this source code is governed by a BSD-style license
	 *  that can be found in the LICENSE file in the root of the source
	 *  tree.
	 */
    function shimGetDisplayMedia$2(window, getSourceId) {
        if (window.navigator.mediaDevices &&
            'getDisplayMedia' in window.navigator.mediaDevices) {
            return;
        }
        if (!(window.navigator.mediaDevices)) {
            return;
        }
        // getSourceId is a function that returns a promise resolving with
        // the sourceId of the screen/window/tab to be shared.
        if (typeof getSourceId !== 'function') {
            console.error('shimGetDisplayMedia: getSourceId argument is not ' +
                'a function');
            return;
        }
        window.navigator.mediaDevices.getDisplayMedia =
            function getDisplayMedia(constraints) {
                return getSourceId(constraints)
                    .then(sourceId => {
                        const widthSpecified = constraints.video && constraints.video.width;
                        const heightSpecified = constraints.video &&
                            constraints.video.height;
                        const frameRateSpecified = constraints.video &&
                            constraints.video.frameRate;
                        constraints.video = {
                            mandatory: {
                                chromeMediaSource: 'desktop',
                                chromeMediaSourceId: sourceId,
                                maxFrameRate: frameRateSpecified || 3
                            }
                        };
                        if (widthSpecified) {
                            constraints.video.mandatory.maxWidth = widthSpecified;
                        }
                        if (heightSpecified) {
                            constraints.video.mandatory.maxHeight = heightSpecified;
                        }
                        return window.navigator.mediaDevices.getUserMedia(constraints);
                    });
            };
    }

    /*
	 *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
	 *
	 *  Use of this source code is governed by a BSD-style license
	 *  that can be found in the LICENSE file in the root of the source
	 *  tree.
	 */

    function shimMediaStream(window) {
        window.MediaStream = window.MediaStream || window.webkitMediaStream;
    }

    function shimOnTrack$1(window) {
        if (typeof window === 'object' && window.RTCPeerConnection && !('ontrack' in
            window.RTCPeerConnection.prototype)) {
            Object.defineProperty(window.RTCPeerConnection.prototype, 'ontrack', {
                get() {
                    return this._ontrack;
                },
                set(f) {
                    if (this._ontrack) {
                        this.removeEventListener('track', this._ontrack);
                    }
                    this.addEventListener('track', this._ontrack = f);
                },
                enumerable: true,
                configurable: true
            });
            const origSetRemoteDescription =
                window.RTCPeerConnection.prototype.setRemoteDescription;
            window.RTCPeerConnection.prototype.setRemoteDescription =
                function setRemoteDescription() {
                    if (!this._ontrackpoly) {
                        this._ontrackpoly = (e) => {
                            // onaddstream does not fire when a track is added to an existing
                            // stream. But stream.onaddtrack is implemented so we use that.
                            e.stream.addEventListener('addtrack', te => {
                                let receiver;
                                if (window.RTCPeerConnection.prototype.getReceivers) {
                                    receiver = this.getReceivers()
                                        .find(r => r.track && r.track.id === te.track.id);
                                } else {
                                    receiver = {track: te.track};
                                }

                                const event = new Event('track');
                                event.track = te.track;
                                event.receiver = receiver;
                                event.transceiver = {receiver};
                                event.streams = [e.stream];
                                this.dispatchEvent(event);
                            });
                            e.stream.getTracks().forEach(track => {
                                let receiver;
                                if (window.RTCPeerConnection.prototype.getReceivers) {
                                    receiver = this.getReceivers()
                                        .find(r => r.track && r.track.id === track.id);
                                } else {
                                    receiver = {track};
                                }
                                const event = new Event('track');
                                event.track = track;
                                event.receiver = receiver;
                                event.transceiver = {receiver};
                                event.streams = [e.stream];
                                this.dispatchEvent(event);
                            });
                        };
                        this.addEventListener('addstream', this._ontrackpoly);
                    }
                    return origSetRemoteDescription.apply(this, arguments);
                };
        } else {
            // even if RTCRtpTransceiver is in window, it is only used and
            // emitted in unified-plan. Unfortunately this means we need
            // to unconditionally wrap the event.
            wrapPeerConnectionEvent(window, 'track', e => {
                if (!e.transceiver) {
                    Object.defineProperty(e, 'transceiver',
                        {value: {receiver: e.receiver}});
                }
                return e;
            });
        }
    }

    function shimGetSendersWithDtmf(window) {
        // Overrides addTrack/removeTrack, depends on shimAddTrackRemoveTrack.
        if (typeof window === 'object' && window.RTCPeerConnection &&
            !('getSenders' in window.RTCPeerConnection.prototype) &&
            'createDTMFSender' in window.RTCPeerConnection.prototype) {
            const shimSenderWithDtmf = function (pc, track) {
                return {
                    track,
                    get dtmf() {
                        if (this._dtmf === undefined) {
                            if (track.kind === 'audio') {
                                this._dtmf = pc.createDTMFSender(track);
                            } else {
                                this._dtmf = null;
                            }
                        }
                        return this._dtmf;
                    },
                    _pc: pc
                };
            };

            // augment addTrack when getSenders is not available.
            if (!window.RTCPeerConnection.prototype.getSenders) {
                window.RTCPeerConnection.prototype.getSenders = function getSenders() {
                    this._senders = this._senders || [];
                    return this._senders.slice(); // return a copy of the internal state.
                };
                const origAddTrack = window.RTCPeerConnection.prototype.addTrack;
                window.RTCPeerConnection.prototype.addTrack =
                    function addTrack(track, stream) {
                        let sender = origAddTrack.apply(this, arguments);
                        if (!sender) {
                            sender = shimSenderWithDtmf(this, track);
                            this._senders.push(sender);
                        }
                        return sender;
                    };

                const origRemoveTrack = window.RTCPeerConnection.prototype.removeTrack;
                window.RTCPeerConnection.prototype.removeTrack =
                    function removeTrack(sender) {
                        origRemoveTrack.apply(this, arguments);
                        const idx = this._senders.indexOf(sender);
                        if (idx !== -1) {
                            this._senders.splice(idx, 1);
                        }
                    };
            }
            const origAddStream = window.RTCPeerConnection.prototype.addStream;
            window.RTCPeerConnection.prototype.addStream = function addStream(stream) {
                this._senders = this._senders || [];
                origAddStream.apply(this, [stream]);
                stream.getTracks().forEach(track => {
                    this._senders.push(shimSenderWithDtmf(this, track));
                });
            };

            const origRemoveStream = window.RTCPeerConnection.prototype.removeStream;
            window.RTCPeerConnection.prototype.removeStream =
                function removeStream(stream) {
                    this._senders = this._senders || [];
                    origRemoveStream.apply(this, [stream]);

                    stream.getTracks().forEach(track => {
                        const sender = this._senders.find(s => s.track === track);
                        if (sender) { // remove sender
                            this._senders.splice(this._senders.indexOf(sender), 1);
                        }
                    });
                };
        } else if (typeof window === 'object' && window.RTCPeerConnection &&
            'getSenders' in window.RTCPeerConnection.prototype &&
            'createDTMFSender' in window.RTCPeerConnection.prototype &&
            window.RTCRtpSender &&
            !('dtmf' in window.RTCRtpSender.prototype)) {
            const origGetSenders = window.RTCPeerConnection.prototype.getSenders;
            window.RTCPeerConnection.prototype.getSenders = function getSenders() {
                const senders = origGetSenders.apply(this, []);
                senders.forEach(sender => sender._pc = this);
                return senders;
            };

            Object.defineProperty(window.RTCRtpSender.prototype, 'dtmf', {
                get() {
                    if (this._dtmf === undefined) {
                        if (this.track.kind === 'audio') {
                            this._dtmf = this._pc.createDTMFSender(this.track);
                        } else {
                            this._dtmf = null;
                        }
                    }
                    return this._dtmf;
                }
            });
        }
    }

    function shimGetStats(window) {
        if (!window.RTCPeerConnection) {
            return;
        }

        const origGetStats = window.RTCPeerConnection.prototype.getStats;
        window.RTCPeerConnection.prototype.getStats = function getStats() {
            const [selector, onSucc, onErr] = arguments;

            // If selector is a function then we are in the old style stats so just
            // pass back the original getStats format to avoid breaking old users.
            if (arguments.length > 0 && typeof selector === 'function') {
                return origGetStats.apply(this, arguments);
            }

            // When spec-style getStats is supported, return those when called with
            // either no arguments or the selector argument is null.
            if (origGetStats.length === 0 && (arguments.length === 0 ||
                typeof selector !== 'function')) {
                return origGetStats.apply(this, []);
            }

            const fixChromeStats_ = function (response) {
                const standardReport = {};
                const reports = response.result();
                reports.forEach(report => {
                    const standardStats = {
                        id: report.id,
                        timestamp: report.timestamp,
                        type: {
                            localcandidate: 'local-candidate',
                            remotecandidate: 'remote-candidate'
                        }[report.type] || report.type
                    };
                    report.names().forEach(name => {
                        standardStats[name] = report.stat(name);
                    });
                    standardReport[standardStats.id] = standardStats;
                });

                return standardReport;
            };

            // shim getStats with maplike support
            const makeMapStats = function (stats) {
                return new Map(Object.keys(stats).map(key => [key, stats[key]]));
            };

            if (arguments.length >= 2) {
                const successCallbackWrapper_ = function (response) {
                    onSucc(makeMapStats(fixChromeStats_(response)));
                };

                return origGetStats.apply(this, [successCallbackWrapper_,
                    selector]);
            }

            // promise-support
            return new Promise((resolve, reject) => {
                origGetStats.apply(this, [
                    function (response) {
                        resolve(makeMapStats(fixChromeStats_(response)));
                    }, reject]);
            }).then(onSucc, onErr);
        };
    }

    function shimSenderReceiverGetStats(window) {
        if (!(typeof window === 'object' && window.RTCPeerConnection &&
            window.RTCRtpSender && window.RTCRtpReceiver)) {
            return;
        }

        // shim sender stats.
        if (!('getStats' in window.RTCRtpSender.prototype)) {
            const origGetSenders = window.RTCPeerConnection.prototype.getSenders;
            if (origGetSenders) {
                window.RTCPeerConnection.prototype.getSenders = function getSenders() {
                    const senders = origGetSenders.apply(this, []);
                    senders.forEach(sender => sender._pc = this);
                    return senders;
                };
            }

            const origAddTrack = window.RTCPeerConnection.prototype.addTrack;
            if (origAddTrack) {
                window.RTCPeerConnection.prototype.addTrack = function addTrack() {
                    const sender = origAddTrack.apply(this, arguments);
                    sender._pc = this;
                    return sender;
                };
            }
            window.RTCRtpSender.prototype.getStats = function getStats() {
                const sender = this;
                return this._pc.getStats().then(result =>
                    /* Note: this will include stats of all senders that
	         *   send a track with the same id as sender.track as
	         *   it is not possible to identify the RTCRtpSender.
	         */
                    filterStats(result, sender.track, true));
            };
        }

        // shim receiver stats.
        if (!('getStats' in window.RTCRtpReceiver.prototype)) {
            const origGetReceivers = window.RTCPeerConnection.prototype.getReceivers;
            if (origGetReceivers) {
                window.RTCPeerConnection.prototype.getReceivers =
                    function getReceivers() {
                        const receivers = origGetReceivers.apply(this, []);
                        receivers.forEach(receiver => receiver._pc = this);
                        return receivers;
                    };
            }
            wrapPeerConnectionEvent(window, 'track', e => {
                e.receiver._pc = e.srcElement;
                return e;
            });
            window.RTCRtpReceiver.prototype.getStats = function getStats() {
                const receiver = this;
                return this._pc.getStats().then(result =>
                    filterStats(result, receiver.track, false));
            };
        }

        if (!('getStats' in window.RTCRtpSender.prototype &&
            'getStats' in window.RTCRtpReceiver.prototype)) {
            return;
        }

        // shim RTCPeerConnection.getStats(track).
        const origGetStats = window.RTCPeerConnection.prototype.getStats;
        window.RTCPeerConnection.prototype.getStats = function getStats() {
            if (arguments.length > 0 &&
                arguments[0] instanceof window.MediaStreamTrack) {
                const track = arguments[0];
                let sender;
                let receiver;
                let err;
                this.getSenders().forEach(s => {
                    if (s.track === track) {
                        if (sender) {
                            err = true;
                        } else {
                            sender = s;
                        }
                    }
                });
                this.getReceivers().forEach(r => {
                    if (r.track === track) {
                        if (receiver) {
                            err = true;
                        } else {
                            receiver = r;
                        }
                    }
                    return r.track === track;
                });
                if (err || (sender && receiver)) {
                    return Promise.reject(new DOMException(
                        'There are more than one sender or receiver for the track.',
                        'InvalidAccessError'));
                } else if (sender) {
                    return sender.getStats();
                } else if (receiver) {
                    return receiver.getStats();
                }
                return Promise.reject(new DOMException(
                    'There is no sender or receiver for the track.',
                    'InvalidAccessError'));
            }
            return origGetStats.apply(this, arguments);
        };
    }

    function shimAddTrackRemoveTrackWithNative(window) {
        // shim addTrack/removeTrack with native variants in order to make
        // the interactions with legacy getLocalStreams behave as in other browsers.
        // Keeps a mapping stream.id => [stream, rtpsenders...]
        window.RTCPeerConnection.prototype.getLocalStreams =
            function getLocalStreams() {
                this._shimmedLocalStreams = this._shimmedLocalStreams || {};
                return Object.keys(this._shimmedLocalStreams)
                    .map(streamId => this._shimmedLocalStreams[streamId][0]);
            };

        const origAddTrack = window.RTCPeerConnection.prototype.addTrack;
        window.RTCPeerConnection.prototype.addTrack =
            function addTrack(track, stream) {
                if (!stream) {
                    return origAddTrack.apply(this, arguments);
                }
                this._shimmedLocalStreams = this._shimmedLocalStreams || {};

                const sender = origAddTrack.apply(this, arguments);
                if (!this._shimmedLocalStreams[stream.id]) {
                    this._shimmedLocalStreams[stream.id] = [stream, sender];
                } else if (this._shimmedLocalStreams[stream.id].indexOf(sender) === -1) {
                    this._shimmedLocalStreams[stream.id].push(sender);
                }
                return sender;
            };

        const origAddStream = window.RTCPeerConnection.prototype.addStream;
        window.RTCPeerConnection.prototype.addStream = function addStream(stream) {
            this._shimmedLocalStreams = this._shimmedLocalStreams || {};

            stream.getTracks().forEach(track => {
                const alreadyExists = this.getSenders().find(s => s.track === track);
                if (alreadyExists) {
                    throw new DOMException('Track already exists.',
                        'InvalidAccessError');
                }
            });
            const existingSenders = this.getSenders();
            origAddStream.apply(this, arguments);
            const newSenders = this.getSenders()
                .filter(newSender => existingSenders.indexOf(newSender) === -1);
            this._shimmedLocalStreams[stream.id] = [stream].concat(newSenders);
        };

        const origRemoveStream = window.RTCPeerConnection.prototype.removeStream;
        window.RTCPeerConnection.prototype.removeStream =
            function removeStream(stream) {
                this._shimmedLocalStreams = this._shimmedLocalStreams || {};
                delete this._shimmedLocalStreams[stream.id];
                return origRemoveStream.apply(this, arguments);
            };

        const origRemoveTrack = window.RTCPeerConnection.prototype.removeTrack;
        window.RTCPeerConnection.prototype.removeTrack =
            function removeTrack(sender) {
                this._shimmedLocalStreams = this._shimmedLocalStreams || {};
                if (sender) {
                    Object.keys(this._shimmedLocalStreams).forEach(streamId => {
                        const idx = this._shimmedLocalStreams[streamId].indexOf(sender);
                        if (idx !== -1) {
                            this._shimmedLocalStreams[streamId].splice(idx, 1);
                        }
                        if (this._shimmedLocalStreams[streamId].length === 1) {
                            delete this._shimmedLocalStreams[streamId];
                        }
                    });
                }
                return origRemoveTrack.apply(this, arguments);
            };
    }

    function shimAddTrackRemoveTrack(window, browserDetails) {
        if (!window.RTCPeerConnection) {
            return;
        }
        // shim addTrack and removeTrack.
        if (window.RTCPeerConnection.prototype.addTrack &&
            browserDetails.version >= 65) {
            return shimAddTrackRemoveTrackWithNative(window);
        }

        // also shim pc.getLocalStreams when addTrack is shimmed
        // to return the original streams.
        const origGetLocalStreams = window.RTCPeerConnection.prototype
            .getLocalStreams;
        window.RTCPeerConnection.prototype.getLocalStreams =
            function getLocalStreams() {
                const nativeStreams = origGetLocalStreams.apply(this);
                this._reverseStreams = this._reverseStreams || {};
                return nativeStreams.map(stream => this._reverseStreams[stream.id]);
            };

        const origAddStream = window.RTCPeerConnection.prototype.addStream;
        window.RTCPeerConnection.prototype.addStream = function addStream(stream) {
            this._streams = this._streams || {};
            this._reverseStreams = this._reverseStreams || {};

            stream.getTracks().forEach(track => {
                const alreadyExists = this.getSenders().find(s => s.track === track);
                if (alreadyExists) {
                    throw new DOMException('Track already exists.',
                        'InvalidAccessError');
                }
            });
            // Add identity mapping for consistency with addTrack.
            // Unless this is being used with a stream from addTrack.
            if (!this._reverseStreams[stream.id]) {
                const newStream = new window.MediaStream(stream.getTracks());
                this._streams[stream.id] = newStream;
                this._reverseStreams[newStream.id] = stream;
                stream = newStream;
            }
            origAddStream.apply(this, [stream]);
        };

        const origRemoveStream = window.RTCPeerConnection.prototype.removeStream;
        window.RTCPeerConnection.prototype.removeStream =
            function removeStream(stream) {
                this._streams = this._streams || {};
                this._reverseStreams = this._reverseStreams || {};

                origRemoveStream.apply(this, [(this._streams[stream.id] || stream)]);
                delete this._reverseStreams[(this._streams[stream.id] ?
                    this._streams[stream.id].id : stream.id)];
                delete this._streams[stream.id];
            };

        window.RTCPeerConnection.prototype.addTrack =
            function addTrack(track, stream) {
                if (this.signalingState === 'closed') {
                    throw new DOMException(
                        'The RTCPeerConnection\'s signalingState is \'closed\'.',
                        'InvalidStateError');
                }
                const streams = [].slice.call(arguments, 1);
                if (streams.length !== 1 ||
                    !streams[0].getTracks().find(t => t === track)) {
                    // this is not fully correct but all we can manage without
                    // [[associated MediaStreams]] internal slot.
                    throw new DOMException(
                        'The adapter.js addTrack polyfill only supports a single ' +
                        ' stream which is associated with the specified track.',
                        'NotSupportedError');
                }

                const alreadyExists = this.getSenders().find(s => s.track === track);
                if (alreadyExists) {
                    throw new DOMException('Track already exists.',
                        'InvalidAccessError');
                }

                this._streams = this._streams || {};
                this._reverseStreams = this._reverseStreams || {};
                const oldStream = this._streams[stream.id];
                if (oldStream) {
                    // this is using odd Chrome behaviour, use with caution:
                    // https://bugs.chromium.org/p/webrtc/issues/detail?id=7815
                    // Note: we rely on the high-level addTrack/dtmf shim to
                    // create the sender with a dtmf sender.
                    oldStream.addTrack(track);

                    // Trigger ONN async.
                    Promise.resolve().then(() => {
                        this.dispatchEvent(new Event('negotiationneeded'));
                    });
                } else {
                    const newStream = new window.MediaStream([track]);
                    this._streams[stream.id] = newStream;
                    this._reverseStreams[newStream.id] = stream;
                    this.addStream(newStream);
                }
                return this.getSenders().find(s => s.track === track);
            };

        // replace the internal stream id with the external one and
        // vice versa.
        function replaceInternalStreamId(pc, description) {
            let sdp = description.sdp;
            Object.keys(pc._reverseStreams || []).forEach(internalId => {
                const externalStream = pc._reverseStreams[internalId];
                const internalStream = pc._streams[externalStream.id];
                sdp = sdp.replace(new RegExp(internalStream.id, 'g'),
                    externalStream.id);
            });
            return new RTCSessionDescription({
                type: description.type,
                sdp
            });
        }

        function replaceExternalStreamId(pc, description) {
            let sdp = description.sdp;
            Object.keys(pc._reverseStreams || []).forEach(internalId => {
                const externalStream = pc._reverseStreams[internalId];
                const internalStream = pc._streams[externalStream.id];
                sdp = sdp.replace(new RegExp(externalStream.id, 'g'),
                    internalStream.id);
            });
            return new RTCSessionDescription({
                type: description.type,
                sdp
            });
        }

        ['createOffer', 'createAnswer'].forEach(function (method) {
            const nativeMethod = window.RTCPeerConnection.prototype[method];
            const methodObj = {
                [method]() {
                    const args = arguments;
                    const isLegacyCall = arguments.length &&
                        typeof arguments[0] === 'function';
                    if (isLegacyCall) {
                        return nativeMethod.apply(this, [
                            (description) => {
                                const desc = replaceInternalStreamId(this, description);
                                args[0].apply(null, [desc]);
                            },
                            (err) => {
                                if (args[1]) {
                                    args[1].apply(null, err);
                                }
                            }, arguments[2]
                        ]);
                    }
                    return nativeMethod.apply(this, arguments)
                        .then(description => replaceInternalStreamId(this, description));
                }
            };
            window.RTCPeerConnection.prototype[method] = methodObj[method];
        });

        const origSetLocalDescription =
            window.RTCPeerConnection.prototype.setLocalDescription;
        window.RTCPeerConnection.prototype.setLocalDescription =
            function setLocalDescription() {
                if (!arguments.length || !arguments[0].type) {
                    return origSetLocalDescription.apply(this, arguments);
                }
                arguments[0] = replaceExternalStreamId(this, arguments[0]);
                return origSetLocalDescription.apply(this, arguments);
            };

        // TODO: mangle getStats: https://w3c.github.io/webrtc-stats/#dom-rtcmediastreamstats-streamidentifier

        const origLocalDescription = Object.getOwnPropertyDescriptor(
            window.RTCPeerConnection.prototype, 'localDescription');
        Object.defineProperty(window.RTCPeerConnection.prototype,
            'localDescription', {
                get() {
                    const description = origLocalDescription.get.apply(this);
                    if (description.type === '') {
                        return description;
                    }
                    return replaceInternalStreamId(this, description);
                }
            });

        window.RTCPeerConnection.prototype.removeTrack =
            function removeTrack(sender) {
                if (this.signalingState === 'closed') {
                    throw new DOMException(
                        'The RTCPeerConnection\'s signalingState is \'closed\'.',
                        'InvalidStateError');
                }
                // We can not yet check for sender instanceof RTCRtpSender
                // since we shim RTPSender. So we check if sender._pc is set.
                if (!sender._pc) {
                    throw new DOMException('Argument 1 of RTCPeerConnection.removeTrack ' +
                        'does not implement interface RTCRtpSender.', 'TypeError');
                }
                const isLocal = sender._pc === this;
                if (!isLocal) {
                    throw new DOMException('Sender was not created by this connection.',
                        'InvalidAccessError');
                }

                // Search for the native stream the senders track belongs to.
                this._streams = this._streams || {};
                let stream;
                Object.keys(this._streams).forEach(streamid => {
                    const hasTrack = this._streams[streamid].getTracks()
                        .find(track => sender.track === track);
                    if (hasTrack) {
                        stream = this._streams[streamid];
                    }
                });

                if (stream) {
                    if (stream.getTracks().length === 1) {
                        // if this is the last track of the stream, remove the stream. This
                        // takes care of any shimmed _senders.
                        this.removeStream(this._reverseStreams[stream.id]);
                    } else {
                        // relying on the same odd chrome behaviour as above.
                        stream.removeTrack(sender.track);
                    }
                    this.dispatchEvent(new Event('negotiationneeded'));
                }
            };
    }

    function shimPeerConnection$2(window, browserDetails) {
        if (!window.RTCPeerConnection && window.webkitRTCPeerConnection) {
            // very basic support for old versions.
            window.RTCPeerConnection = window.webkitRTCPeerConnection;
        }
        if (!window.RTCPeerConnection) {
            return;
        }

        // shim implicit creation of RTCSessionDescription/RTCIceCandidate
        if (browserDetails.version < 53) {
            ['setLocalDescription', 'setRemoteDescription', 'addIceCandidate']
                .forEach(function (method) {
                    const nativeMethod = window.RTCPeerConnection.prototype[method];
                    const methodObj = {
                        [method]() {
                            arguments[0] = new ((method === 'addIceCandidate') ?
                                window.RTCIceCandidate :
                                window.RTCSessionDescription)(arguments[0]);
                            return nativeMethod.apply(this, arguments);
                        }
                    };
                    window.RTCPeerConnection.prototype[method] = methodObj[method];
                });
        }
    }

    // Attempt to fix ONN in plan-b mode.
    function fixNegotiationNeeded(window, browserDetails) {
        wrapPeerConnectionEvent(window, 'negotiationneeded', e => {
            const pc = e.target;
            if (browserDetails.version < 72 || (pc.getConfiguration &&
                pc.getConfiguration().sdpSemantics === 'plan-b')) {
                if (pc.signalingState !== 'stable') {
                    return;
                }
            }
            return e;
        });
    }

    var chromeShim = /*#__PURE__*/Object.freeze({
        __proto__: null,
        shimMediaStream: shimMediaStream,
        shimOnTrack: shimOnTrack$1,
        shimGetSendersWithDtmf: shimGetSendersWithDtmf,
        shimGetStats: shimGetStats,
        shimSenderReceiverGetStats: shimSenderReceiverGetStats,
        shimAddTrackRemoveTrackWithNative: shimAddTrackRemoveTrackWithNative,
        shimAddTrackRemoveTrack: shimAddTrackRemoveTrack,
        shimPeerConnection: shimPeerConnection$2,
        fixNegotiationNeeded: fixNegotiationNeeded,
        shimGetUserMedia: shimGetUserMedia$3,
        shimGetDisplayMedia: shimGetDisplayMedia$2
    });

    /*
	 *  Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
	 *
	 *  Use of this source code is governed by a BSD-style license
	 *  that can be found in the LICENSE file in the root of the source
	 *  tree.
	 */
    // Edge does not like
    // 1) stun: filtered after 14393 unless ?transport=udp is present
    // 2) turn: that does not have all of turn:host:port?transport=udp
    // 3) turn: with ipv6 addresses
    // 4) turn: occurring muliple times
    function filterIceServers$1(iceServers, edgeVersion) {
        let hasTurn = false;
        iceServers = JSON.parse(JSON.stringify(iceServers));
        return iceServers.filter(server => {
            if (server && (server.urls || server.url)) {
                let urls = server.urls || server.url;
                if (server.url && !server.urls) {
                    deprecated('RTCIceServer.url', 'RTCIceServer.urls');
                }
                const isString = typeof urls === 'string';
                if (isString) {
                    urls = [urls];
                }
                urls = urls.filter(url => {
                    // filter STUN unconditionally.
                    if (url.indexOf('stun:') === 0) {
                        return false;
                    }

                    const validTurn = url.startsWith('turn') &&
                        !url.startsWith('turn:[') &&
                        url.includes('transport=udp');
                    if (validTurn && !hasTurn) {
                        hasTurn = true;
                        return true;
                    }
                    return validTurn && !hasTurn;
                });

                delete server.url;
                server.urls = isString ? urls[0] : urls;
                return !!urls.length;
            }
        });
    }

    function createCommonjsModule(fn) {
        var module = {exports: {}};
        return fn(module, module.exports), module.exports;
    }

    /* eslint-env node */

    var sdp = createCommonjsModule(function (module) {

        // SDP helpers.
        var SDPUtils = {};

        // Generate an alphanumeric identifier for cname or mids.
        // TODO: use UUIDs instead? https://gist.github.com/jed/982883
        SDPUtils.generateIdentifier = function () {
            return Math.random().toString(36).substr(2, 10);
        };

        // The RTCP CNAME used by all peerconnections from the same JS.
        SDPUtils.localCName = SDPUtils.generateIdentifier();

        // Splits SDP into lines, dealing with both CRLF and LF.
        SDPUtils.splitLines = function (blob) {
            return blob.trim().split('\n').map(function (line) {
                return line.trim();
            });
        };
        // Splits SDP into sessionpart and mediasections. Ensures CRLF.
        SDPUtils.splitSections = function (blob) {
            var parts = blob.split('\nm=');
            return parts.map(function (part, index) {
                return (index > 0 ? 'm=' + part : part).trim() + '\r\n';
            });
        };

        // returns the session description.
        SDPUtils.getDescription = function (blob) {
            var sections = SDPUtils.splitSections(blob);
            return sections && sections[0];
        };

        // returns the individual media sections.
        SDPUtils.getMediaSections = function (blob) {
            var sections = SDPUtils.splitSections(blob);
            sections.shift();
            return sections;
        };

        // Returns lines that start with a certain prefix.
        SDPUtils.matchPrefix = function (blob, prefix) {
            return SDPUtils.splitLines(blob).filter(function (line) {
                return line.indexOf(prefix) === 0;
            });
        };

        // Parses an ICE candidate line. Sample input:
        // candidate:702786350 2 udp 41819902 8.8.8.8 60769 typ relay raddr 8.8.8.8
        // rport 55996"
        SDPUtils.parseCandidate = function (line) {
            var parts;
            // Parse both variants.
            if (line.indexOf('a=candidate:') === 0) {
                parts = line.substring(12).split(' ');
            } else {
                parts = line.substring(10).split(' ');
            }

            var candidate = {
                foundation: parts[0],
                component: parseInt(parts[1], 10),
                protocol: parts[2].toLowerCase(),
                priority: parseInt(parts[3], 10),
                ip: parts[4],
                address: parts[4], // address is an alias for ip.
                port: parseInt(parts[5], 10),
                // skip parts[6] == 'typ'
                type: parts[7]
            };

            for (var i = 8; i < parts.length; i += 2) {
                switch (parts[i]) {
                    case 'raddr':
                        candidate.relatedAddress = parts[i + 1];
                        break;
                    case 'rport':
                        candidate.relatedPort = parseInt(parts[i + 1], 10);
                        break;
                    case 'tcptype':
                        candidate.tcpType = parts[i + 1];
                        break;
                    case 'ufrag':
                        candidate.ufrag = parts[i + 1]; // for backward compability.
                        candidate.usernameFragment = parts[i + 1];
                        break;
                    default: // extension handling, in particular ufrag
                        candidate[parts[i]] = parts[i + 1];
                        break;
                }
            }
            return candidate;
        };

        // Translates a candidate object into SDP candidate attribute.
        SDPUtils.writeCandidate = function (candidate) {
            var sdp = [];
            sdp.push(candidate.foundation);
            sdp.push(candidate.component);
            sdp.push(candidate.protocol.toUpperCase());
            sdp.push(candidate.priority);
            sdp.push(candidate.address || candidate.ip);
            sdp.push(candidate.port);

            var type = candidate.type;
            sdp.push('typ');
            sdp.push(type);
            if (type !== 'host' && candidate.relatedAddress &&
                candidate.relatedPort) {
                sdp.push('raddr');
                sdp.push(candidate.relatedAddress);
                sdp.push('rport');
                sdp.push(candidate.relatedPort);
            }
            if (candidate.tcpType && candidate.protocol.toLowerCase() === 'tcp') {
                sdp.push('tcptype');
                sdp.push(candidate.tcpType);
            }
            if (candidate.usernameFragment || candidate.ufrag) {
                sdp.push('ufrag');
                sdp.push(candidate.usernameFragment || candidate.ufrag);
            }
            return 'candidate:' + sdp.join(' ');
        };

        // Parses an ice-options line, returns an array of option tags.
        // a=ice-options:foo bar
        SDPUtils.parseIceOptions = function (line) {
            return line.substr(14).split(' ');
        };

        // Parses an rtpmap line, returns RTCRtpCoddecParameters. Sample input:
        // a=rtpmap:111 opus/48000/2
        SDPUtils.parseRtpMap = function (line) {
            var parts = line.substr(9).split(' ');
            var parsed = {
                payloadType: parseInt(parts.shift(), 10) // was: id
            };

            parts = parts[0].split('/');

            parsed.name = parts[0];
            parsed.clockRate = parseInt(parts[1], 10); // was: clockrate
            parsed.channels = parts.length === 3 ? parseInt(parts[2], 10) : 1;
            // legacy alias, got renamed back to channels in ORTC.
            parsed.numChannels = parsed.channels;
            return parsed;
        };

        // Generate an a=rtpmap line from RTCRtpCodecCapability or
        // RTCRtpCodecParameters.
        SDPUtils.writeRtpMap = function (codec) {
            var pt = codec.payloadType;
            if (codec.preferredPayloadType !== undefined) {
                pt = codec.preferredPayloadType;
            }
            var channels = codec.channels || codec.numChannels || 1;
            return 'a=rtpmap:' + pt + ' ' + codec.name + '/' + codec.clockRate +
                (channels !== 1 ? '/' + channels : '') + '\r\n';
        };

        // Parses an a=extmap line (headerextension from RFC 5285). Sample input:
        // a=extmap:2 urn:ietf:params:rtp-hdrext:toffset
        // a=extmap:2/sendonly urn:ietf:params:rtp-hdrext:toffset
        SDPUtils.parseExtmap = function (line) {
            var parts = line.substr(9).split(' ');
            return {
                id: parseInt(parts[0], 10),
                direction: parts[0].indexOf('/') > 0 ? parts[0].split('/')[1] : 'sendrecv',
                uri: parts[1]
            };
        };

        // Generates a=extmap line from RTCRtpHeaderExtensionParameters or
        // RTCRtpHeaderExtension.
        SDPUtils.writeExtmap = function (headerExtension) {
            return 'a=extmap:' + (headerExtension.id || headerExtension.preferredId) +
                (headerExtension.direction && headerExtension.direction !== 'sendrecv'
                    ? '/' + headerExtension.direction
                    : '') +
                ' ' + headerExtension.uri + '\r\n';
        };

        // Parses an ftmp line, returns dictionary. Sample input:
        // a=fmtp:96 vbr=on;cng=on
        // Also deals with vbr=on; cng=on
        SDPUtils.parseFmtp = function (line) {
            var parsed = {};
            var kv;
            var parts = line.substr(line.indexOf(' ') + 1).split(';');
            for (var j = 0; j < parts.length; j++) {
                kv = parts[j].trim().split('=');
                parsed[kv[0].trim()] = kv[1];
            }
            return parsed;
        };

        // Generates an a=ftmp line from RTCRtpCodecCapability or RTCRtpCodecParameters.
        SDPUtils.writeFmtp = function (codec) {
            var line = '';
            var pt = codec.payloadType;
            if (codec.preferredPayloadType !== undefined) {
                pt = codec.preferredPayloadType;
            }
            if (codec.parameters && Object.keys(codec.parameters).length) {
                var params = [];
                Object.keys(codec.parameters).forEach(function (param) {
                    if (codec.parameters[param]) {
                        params.push(param + '=' + codec.parameters[param]);
                    } else {
                        params.push(param);
                    }
                });
                line += 'a=fmtp:' + pt + ' ' + params.join(';') + '\r\n';
            }
            return line;
        };

        // Parses an rtcp-fb line, returns RTCPRtcpFeedback object. Sample input:
        // a=rtcp-fb:98 nack rpsi
        SDPUtils.parseRtcpFb = function (line) {
            var parts = line.substr(line.indexOf(' ') + 1).split(' ');
            return {
                type: parts.shift(),
                parameter: parts.join(' ')
            };
        };
        // Generate a=rtcp-fb lines from RTCRtpCodecCapability or RTCRtpCodecParameters.
        SDPUtils.writeRtcpFb = function (codec) {
            var lines = '';
            var pt = codec.payloadType;
            if (codec.preferredPayloadType !== undefined) {
                pt = codec.preferredPayloadType;
            }
            if (codec.rtcpFeedback && codec.rtcpFeedback.length) {
                // FIXME: special handling for trr-int?
                codec.rtcpFeedback.forEach(function (fb) {
                    lines += 'a=rtcp-fb:' + pt + ' ' + fb.type +
                        (fb.parameter && fb.parameter.length ? ' ' + fb.parameter : '') +
                        '\r\n';
                });
            }
            return lines;
        };

        // Parses an RFC 5576 ssrc media attribute. Sample input:
        // a=ssrc:3735928559 cname:something
        SDPUtils.parseSsrcMedia = function (line) {
            var sp = line.indexOf(' ');
            var parts = {
                ssrc: parseInt(line.substr(7, sp - 7), 10)
            };
            var colon = line.indexOf(':', sp);
            if (colon > -1) {
                parts.attribute = line.substr(sp + 1, colon - sp - 1);
                parts.value = line.substr(colon + 1);
            } else {
                parts.attribute = line.substr(sp + 1);
            }
            return parts;
        };

        SDPUtils.parseSsrcGroup = function (line) {
            var parts = line.substr(13).split(' ');
            return {
                semantics: parts.shift(),
                ssrcs: parts.map(function (ssrc) {
                    return parseInt(ssrc, 10);
                })
            };
        };

        // Extracts the MID (RFC 5888) from a media section.
        // returns the MID or undefined if no mid line was found.
        SDPUtils.getMid = function (mediaSection) {
            var mid = SDPUtils.matchPrefix(mediaSection, 'a=mid:')[0];
            if (mid) {
                return mid.substr(6);
            }
        };

        SDPUtils.parseFingerprint = function (line) {
            var parts = line.substr(14).split(' ');
            return {
                algorithm: parts[0].toLowerCase(), // algorithm is case-sensitive in Edge.
                value: parts[1]
            };
        };

        // Extracts DTLS parameters from SDP media section or sessionpart.
        // FIXME: for consistency with other functions this should only
        //   get the fingerprint line as input. See also getIceParameters.
        SDPUtils.getDtlsParameters = function (mediaSection, sessionpart) {
            var lines = SDPUtils.matchPrefix(mediaSection + sessionpart,
                'a=fingerprint:');
            // Note: a=setup line is ignored since we use the 'auto' role.
            // Note2: 'algorithm' is not case sensitive except in Edge.
            return {
                role: 'auto',
                fingerprints: lines.map(SDPUtils.parseFingerprint)
            };
        };

        // Serializes DTLS parameters to SDP.
        SDPUtils.writeDtlsParameters = function (params, setupType) {
            var sdp = 'a=setup:' + setupType + '\r\n';
            params.fingerprints.forEach(function (fp) {
                sdp += 'a=fingerprint:' + fp.algorithm + ' ' + fp.value + '\r\n';
            });
            return sdp;
        };

        // Parses a=crypto lines into
        //   https://rawgit.com/aboba/edgertc/master/msortc-rs4.html#dictionary-rtcsrtpsdesparameters-members
        SDPUtils.parseCryptoLine = function (line) {
            var parts = line.substr(9).split(' ');
            return {
                tag: parseInt(parts[0], 10),
                cryptoSuite: parts[1],
                keyParams: parts[2],
                sessionParams: parts.slice(3),
            };
        };

        SDPUtils.writeCryptoLine = function (parameters) {
            return 'a=crypto:' + parameters.tag + ' ' +
                parameters.cryptoSuite + ' ' +
                (typeof parameters.keyParams === 'object'
                    ? SDPUtils.writeCryptoKeyParams(parameters.keyParams)
                    : parameters.keyParams) +
                (parameters.sessionParams ? ' ' + parameters.sessionParams.join(' ') : '') +
                '\r\n';
        };

        // Parses the crypto key parameters into
        //   https://rawgit.com/aboba/edgertc/master/msortc-rs4.html#rtcsrtpkeyparam*
        SDPUtils.parseCryptoKeyParams = function (keyParams) {
            if (keyParams.indexOf('inline:') !== 0) {
                return null;
            }
            var parts = keyParams.substr(7).split('|');
            return {
                keyMethod: 'inline',
                keySalt: parts[0],
                lifeTime: parts[1],
                mkiValue: parts[2] ? parts[2].split(':')[0] : undefined,
                mkiLength: parts[2] ? parts[2].split(':')[1] : undefined,
            };
        };

        SDPUtils.writeCryptoKeyParams = function (keyParams) {
            return keyParams.keyMethod + ':'
                + keyParams.keySalt +
                (keyParams.lifeTime ? '|' + keyParams.lifeTime : '') +
                (keyParams.mkiValue && keyParams.mkiLength
                    ? '|' + keyParams.mkiValue + ':' + keyParams.mkiLength
                    : '');
        };

        // Extracts all SDES paramters.
        SDPUtils.getCryptoParameters = function (mediaSection, sessionpart) {
            var lines = SDPUtils.matchPrefix(mediaSection + sessionpart,
                'a=crypto:');
            return lines.map(SDPUtils.parseCryptoLine);
        };

        // Parses ICE information from SDP media section or sessionpart.
        // FIXME: for consistency with other functions this should only
        //   get the ice-ufrag and ice-pwd lines as input.
        SDPUtils.getIceParameters = function (mediaSection, sessionpart) {
            var ufrag = SDPUtils.matchPrefix(mediaSection + sessionpart,
                'a=ice-ufrag:')[0];
            var pwd = SDPUtils.matchPrefix(mediaSection + sessionpart,
                'a=ice-pwd:')[0];
            if (!(ufrag && pwd)) {
                return null;
            }
            return {
                usernameFragment: ufrag.substr(12),
                password: pwd.substr(10),
            };
        };

        // Serializes ICE parameters to SDP.
        SDPUtils.writeIceParameters = function (params) {
            return 'a=ice-ufrag:' + params.usernameFragment + '\r\n' +
                'a=ice-pwd:' + params.password + '\r\n';
        };

        // Parses the SDP media section and returns RTCRtpParameters.
        SDPUtils.parseRtpParameters = function (mediaSection) {
            var description = {
                codecs: [],
                headerExtensions: [],
                fecMechanisms: [],
                rtcp: []
            };
            var lines = SDPUtils.splitLines(mediaSection);
            var mline = lines[0].split(' ');
            for (var i = 3; i < mline.length; i++) { // find all codecs from mline[3..]
                var pt = mline[i];
                var rtpmapline = SDPUtils.matchPrefix(
                    mediaSection, 'a=rtpmap:' + pt + ' ')[0];
                if (rtpmapline) {
                    var codec = SDPUtils.parseRtpMap(rtpmapline);
                    var fmtps = SDPUtils.matchPrefix(
                        mediaSection, 'a=fmtp:' + pt + ' ');
                    // Only the first a=fmtp:<pt> is considered.
                    codec.parameters = fmtps.length ? SDPUtils.parseFmtp(fmtps[0]) : {};
                    codec.rtcpFeedback = SDPUtils.matchPrefix(
                        mediaSection, 'a=rtcp-fb:' + pt + ' ')
                        .map(SDPUtils.parseRtcpFb);
                    description.codecs.push(codec);
                    // parse FEC mechanisms from rtpmap lines.
                    switch (codec.name.toUpperCase()) {
                        case 'RED':
                        case 'ULPFEC':
                            description.fecMechanisms.push(codec.name.toUpperCase());
                            break;
                    }
                }
            }
            SDPUtils.matchPrefix(mediaSection, 'a=extmap:').forEach(function (line) {
                description.headerExtensions.push(SDPUtils.parseExtmap(line));
            });
            // FIXME: parse rtcp.
            return description;
        };

        // Generates parts of the SDP media section describing the capabilities /
        // parameters.
        SDPUtils.writeRtpDescription = function (kind, caps) {
            var sdp = '';

            // Build the mline.
            sdp += 'm=' + kind + ' ';
            sdp += caps.codecs.length > 0 ? '9' : '0'; // reject if no codecs.
            sdp += ' UDP/TLS/RTP/SAVPF ';
            sdp += caps.codecs.map(function (codec) {
                if (codec.preferredPayloadType !== undefined) {
                    return codec.preferredPayloadType;
                }
                return codec.payloadType;
            }).join(' ') + '\r\n';

            sdp += 'c=IN IP4 0.0.0.0\r\n';
            sdp += 'a=rtcp:9 IN IP4 0.0.0.0\r\n';

            // Add a=rtpmap lines for each codec. Also fmtp and rtcp-fb.
            caps.codecs.forEach(function (codec) {
                sdp += SDPUtils.writeRtpMap(codec);
                sdp += SDPUtils.writeFmtp(codec);
                sdp += SDPUtils.writeRtcpFb(codec);
            });
            var maxptime = 0;
            caps.codecs.forEach(function (codec) {
                if (codec.maxptime > maxptime) {
                    maxptime = codec.maxptime;
                }
            });
            if (maxptime > 0) {
                sdp += 'a=maxptime:' + maxptime + '\r\n';
            }
            sdp += 'a=rtcp-mux\r\n';

            if (caps.headerExtensions) {
                caps.headerExtensions.forEach(function (extension) {
                    sdp += SDPUtils.writeExtmap(extension);
                });
            }
            // FIXME: write fecMechanisms.
            return sdp;
        };

        // Parses the SDP media section and returns an array of
        // RTCRtpEncodingParameters.
        SDPUtils.parseRtpEncodingParameters = function (mediaSection) {
            var encodingParameters = [];
            var description = SDPUtils.parseRtpParameters(mediaSection);
            var hasRed = description.fecMechanisms.indexOf('RED') !== -1;
            var hasUlpfec = description.fecMechanisms.indexOf('ULPFEC') !== -1;

            // filter a=ssrc:... cname:, ignore PlanB-msid
            var ssrcs = SDPUtils.matchPrefix(mediaSection, 'a=ssrc:')
                .map(function (line) {
                    return SDPUtils.parseSsrcMedia(line);
                })
                .filter(function (parts) {
                    return parts.attribute === 'cname';
                });
            var primarySsrc = ssrcs.length > 0 && ssrcs[0].ssrc;
            var secondarySsrc;

            var flows = SDPUtils.matchPrefix(mediaSection, 'a=ssrc-group:FID')
                .map(function (line) {
                    var parts = line.substr(17).split(' ');
                    return parts.map(function (part) {
                        return parseInt(part, 10);
                    });
                });
            if (flows.length > 0 && flows[0].length > 1 && flows[0][0] === primarySsrc) {
                secondarySsrc = flows[0][1];
            }

            description.codecs.forEach(function (codec) {
                if (codec.name.toUpperCase() === 'RTX' && codec.parameters.apt) {
                    var encParam = {
                        ssrc: primarySsrc,
                        codecPayloadType: parseInt(codec.parameters.apt, 10)
                    };
                    if (primarySsrc && secondarySsrc) {
                        encParam.rtx = {ssrc: secondarySsrc};
                    }
                    encodingParameters.push(encParam);
                    if (hasRed) {
                        encParam = JSON.parse(JSON.stringify(encParam));
                        encParam.fec = {
                            ssrc: primarySsrc,
                            mechanism: hasUlpfec ? 'red+ulpfec' : 'red'
                        };
                        encodingParameters.push(encParam);
                    }
                }
            });
            if (encodingParameters.length === 0 && primarySsrc) {
                encodingParameters.push({
                    ssrc: primarySsrc
                });
            }

            // we support both b=AS and b=TIAS but interpret AS as TIAS.
            var bandwidth = SDPUtils.matchPrefix(mediaSection, 'b=');
            if (bandwidth.length) {
                if (bandwidth[0].indexOf('b=TIAS:') === 0) {
                    bandwidth = parseInt(bandwidth[0].substr(7), 10);
                } else if (bandwidth[0].indexOf('b=AS:') === 0) {
                    // use formula from JSEP to convert b=AS to TIAS value.
                    bandwidth = parseInt(bandwidth[0].substr(5), 10) * 1000 * 0.95
                        - (50 * 40 * 8);
                } else {
                    bandwidth = undefined;
                }
                encodingParameters.forEach(function (params) {
                    params.maxBitrate = bandwidth;
                });
            }
            return encodingParameters;
        };

        // parses http://draft.ortc.org/#rtcrtcpparameters*
        SDPUtils.parseRtcpParameters = function (mediaSection) {
            var rtcpParameters = {};

            // Gets the first SSRC. Note tha with RTX there might be multiple
            // SSRCs.
            var remoteSsrc = SDPUtils.matchPrefix(mediaSection, 'a=ssrc:')
                .map(function (line) {
                    return SDPUtils.parseSsrcMedia(line);
                })
                .filter(function (obj) {
                    return obj.attribute === 'cname';
                })[0];
            if (remoteSsrc) {
                rtcpParameters.cname = remoteSsrc.value;
                rtcpParameters.ssrc = remoteSsrc.ssrc;
            }

            // Edge uses the compound attribute instead of reducedSize
            // compound is !reducedSize
            var rsize = SDPUtils.matchPrefix(mediaSection, 'a=rtcp-rsize');
            rtcpParameters.reducedSize = rsize.length > 0;
            rtcpParameters.compound = rsize.length === 0;

            // parses the rtcp-mux attrіbute.
            // Note that Edge does not support unmuxed RTCP.
            var mux = SDPUtils.matchPrefix(mediaSection, 'a=rtcp-mux');
            rtcpParameters.mux = mux.length > 0;

            return rtcpParameters;
        };

        // parses either a=msid: or a=ssrc:... msid lines and returns
        // the id of the MediaStream and MediaStreamTrack.
        SDPUtils.parseMsid = function (mediaSection) {
            var parts;
            var spec = SDPUtils.matchPrefix(mediaSection, 'a=msid:');
            if (spec.length === 1) {
                parts = spec[0].substr(7).split(' ');
                return {stream: parts[0], track: parts[1]};
            }
            var planB = SDPUtils.matchPrefix(mediaSection, 'a=ssrc:')
                .map(function (line) {
                    return SDPUtils.parseSsrcMedia(line);
                })
                .filter(function (msidParts) {
                    return msidParts.attribute === 'msid';
                });
            if (planB.length > 0) {
                parts = planB[0].value.split(' ');
                return {stream: parts[0], track: parts[1]};
            }
        };

        // SCTP
        // parses draft-ietf-mmusic-sctp-sdp-26 first and falls back
        // to draft-ietf-mmusic-sctp-sdp-05
        SDPUtils.parseSctpDescription = function (mediaSection) {
            var mline = SDPUtils.parseMLine(mediaSection);
            var maxSizeLine = SDPUtils.matchPrefix(mediaSection, 'a=max-message-size:');
            var maxMessageSize;
            if (maxSizeLine.length > 0) {
                maxMessageSize = parseInt(maxSizeLine[0].substr(19), 10);
            }
            if (isNaN(maxMessageSize)) {
                maxMessageSize = 65536;
            }
            var sctpPort = SDPUtils.matchPrefix(mediaSection, 'a=sctp-port:');
            if (sctpPort.length > 0) {
                return {
                    port: parseInt(sctpPort[0].substr(12), 10),
                    protocol: mline.fmt,
                    maxMessageSize: maxMessageSize
                };
            }
            var sctpMapLines = SDPUtils.matchPrefix(mediaSection, 'a=sctpmap:');
            if (sctpMapLines.length > 0) {
                var parts = SDPUtils.matchPrefix(mediaSection, 'a=sctpmap:')[0]
                    .substr(10)
                    .split(' ');
                return {
                    port: parseInt(parts[0], 10),
                    protocol: parts[1],
                    maxMessageSize: maxMessageSize
                };
            }
        };

        // SCTP
        // outputs the draft-ietf-mmusic-sctp-sdp-26 version that all browsers
        // support by now receiving in this format, unless we originally parsed
        // as the draft-ietf-mmusic-sctp-sdp-05 format (indicated by the m-line
        // protocol of DTLS/SCTP -- without UDP/ or TCP/)
        SDPUtils.writeSctpDescription = function (media, sctp) {
            var output = [];
            if (media.protocol !== 'DTLS/SCTP') {
                output = [
                    'm=' + media.kind + ' 9 ' + media.protocol + ' ' + sctp.protocol + '\r\n',
                    'c=IN IP4 0.0.0.0\r\n',
                    'a=sctp-port:' + sctp.port + '\r\n'
                ];
            } else {
                output = [
                    'm=' + media.kind + ' 9 ' + media.protocol + ' ' + sctp.port + '\r\n',
                    'c=IN IP4 0.0.0.0\r\n',
                    'a=sctpmap:' + sctp.port + ' ' + sctp.protocol + ' 65535\r\n'
                ];
            }
            if (sctp.maxMessageSize !== undefined) {
                output.push('a=max-message-size:' + sctp.maxMessageSize + '\r\n');
            }
            return output.join('');
        };

        // Generate a session ID for SDP.
        // https://tools.ietf.org/html/draft-ietf-rtcweb-jsep-20#section-5.2.1
        // recommends using a cryptographically random +ve 64-bit value
        // but right now this should be acceptable and within the right range
        SDPUtils.generateSessionId = function () {
            return Math.random().toString().substr(2, 21);
        };

        // Write boilder plate for start of SDP
        // sessId argument is optional - if not supplied it will
        // be generated randomly
        // sessVersion is optional and defaults to 2
        // sessUser is optional and defaults to 'thisisadapterortc'
        SDPUtils.writeSessionBoilerplate = function (sessId, sessVer, sessUser) {
            var sessionId;
            var version = sessVer !== undefined ? sessVer : 2;
            if (sessId) {
                sessionId = sessId;
            } else {
                sessionId = SDPUtils.generateSessionId();
            }
            var user = sessUser || 'thisisadapterortc';
            // FIXME: sess-id should be an NTP timestamp.
            return 'v=0\r\n' +
                'o=' + user + ' ' + sessionId + ' ' + version +
                ' IN IP4 127.0.0.1\r\n' +
                's=-\r\n' +
                't=0 0\r\n';
        };

        SDPUtils.writeMediaSection = function (transceiver, caps, type, stream) {
            var sdp = SDPUtils.writeRtpDescription(transceiver.kind, caps);

            // Map ICE parameters (ufrag, pwd) to SDP.
            sdp += SDPUtils.writeIceParameters(
                transceiver.iceGatherer.getLocalParameters());

            // Map DTLS parameters to SDP.
            sdp += SDPUtils.writeDtlsParameters(
                transceiver.dtlsTransport.getLocalParameters(),
                type === 'offer' ? 'actpass' : 'active');

            sdp += 'a=mid:' + transceiver.mid + '\r\n';

            if (transceiver.direction) {
                sdp += 'a=' + transceiver.direction + '\r\n';
            } else if (transceiver.rtpSender && transceiver.rtpReceiver) {
                sdp += 'a=sendrecv\r\n';
            } else if (transceiver.rtpSender) {
                sdp += 'a=sendonly\r\n';
            } else if (transceiver.rtpReceiver) {
                sdp += 'a=recvonly\r\n';
            } else {
                sdp += 'a=inactive\r\n';
            }

            if (transceiver.rtpSender) {
                // spec.
                var msid = 'msid:' + stream.id + ' ' +
                    transceiver.rtpSender.track.id + '\r\n';
                sdp += 'a=' + msid;

                // for Chrome.
                sdp += 'a=ssrc:' + transceiver.sendEncodingParameters[0].ssrc +
                    ' ' + msid;
                if (transceiver.sendEncodingParameters[0].rtx) {
                    sdp += 'a=ssrc:' + transceiver.sendEncodingParameters[0].rtx.ssrc +
                        ' ' + msid;
                    sdp += 'a=ssrc-group:FID ' +
                        transceiver.sendEncodingParameters[0].ssrc + ' ' +
                        transceiver.sendEncodingParameters[0].rtx.ssrc +
                        '\r\n';
                }
            }
            // FIXME: this should be written by writeRtpDescription.
            sdp += 'a=ssrc:' + transceiver.sendEncodingParameters[0].ssrc +
                ' cname:' + SDPUtils.localCName + '\r\n';
            if (transceiver.rtpSender && transceiver.sendEncodingParameters[0].rtx) {
                sdp += 'a=ssrc:' + transceiver.sendEncodingParameters[0].rtx.ssrc +
                    ' cname:' + SDPUtils.localCName + '\r\n';
            }
            return sdp;
        };

        // Gets the direction from the mediaSection or the sessionpart.
        SDPUtils.getDirection = function (mediaSection, sessionpart) {
            // Look for sendrecv, sendonly, recvonly, inactive, default to sendrecv.
            var lines = SDPUtils.splitLines(mediaSection);
            for (var i = 0; i < lines.length; i++) {
                switch (lines[i]) {
                    case 'a=sendrecv':
                    case 'a=sendonly':
                    case 'a=recvonly':
                    case 'a=inactive':
                        return lines[i].substr(2);
                    // FIXME: What should happen here?
                }
            }
            if (sessionpart) {
                return SDPUtils.getDirection(sessionpart);
            }
            return 'sendrecv';
        };

        SDPUtils.getKind = function (mediaSection) {
            var lines = SDPUtils.splitLines(mediaSection);
            var mline = lines[0].split(' ');
            return mline[0].substr(2);
        };

        SDPUtils.isRejected = function (mediaSection) {
            return mediaSection.split(' ', 2)[1] === '0';
        };

        SDPUtils.parseMLine = function (mediaSection) {
            var lines = SDPUtils.splitLines(mediaSection);
            var parts = lines[0].substr(2).split(' ');
            return {
                kind: parts[0],
                port: parseInt(parts[1], 10),
                protocol: parts[2],
                fmt: parts.slice(3).join(' ')
            };
        };

        SDPUtils.parseOLine = function (mediaSection) {
            var line = SDPUtils.matchPrefix(mediaSection, 'o=')[0];
            var parts = line.substr(2).split(' ');
            return {
                username: parts[0],
                sessionId: parts[1],
                sessionVersion: parseInt(parts[2], 10),
                netType: parts[3],
                addressType: parts[4],
                address: parts[5]
            };
        };

        // a very naive interpretation of a valid SDP.
        SDPUtils.isValidSDP = function (blob) {
            if (typeof blob !== 'string' || blob.length === 0) {
                return false;
            }
            var lines = SDPUtils.splitLines(blob);
            for (var i = 0; i < lines.length; i++) {
                if (lines[i].length < 2 || lines[i].charAt(1) !== '=') {
                    return false;
                }
                // TODO: check the modifier a bit more.
            }
            return true;
        };

        // Expose public methods.
        {
            module.exports = SDPUtils;
        }
    });

    /*
	 *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
	 *
	 *  Use of this source code is governed by a BSD-style license
	 *  that can be found in the LICENSE file in the root of the source
	 *  tree.
	 */


    function fixStatsType(stat) {
        return {
            inboundrtp: 'inbound-rtp',
            outboundrtp: 'outbound-rtp',
            candidatepair: 'candidate-pair',
            localcandidate: 'local-candidate',
            remotecandidate: 'remote-candidate'
        }[stat.type] || stat.type;
    }

    function writeMediaSection(transceiver, caps, type, stream, dtlsRole) {
        var sdp$1 = sdp.writeRtpDescription(transceiver.kind, caps);

        // Map ICE parameters (ufrag, pwd) to SDP.
        sdp$1 += sdp.writeIceParameters(
            transceiver.iceGatherer.getLocalParameters());

        // Map DTLS parameters to SDP.
        sdp$1 += sdp.writeDtlsParameters(
            transceiver.dtlsTransport.getLocalParameters(),
            type === 'offer' ? 'actpass' : dtlsRole || 'active');

        sdp$1 += 'a=mid:' + transceiver.mid + '\r\n';

        if (transceiver.rtpSender && transceiver.rtpReceiver) {
            sdp$1 += 'a=sendrecv\r\n';
        } else if (transceiver.rtpSender) {
            sdp$1 += 'a=sendonly\r\n';
        } else if (transceiver.rtpReceiver) {
            sdp$1 += 'a=recvonly\r\n';
        } else {
            sdp$1 += 'a=inactive\r\n';
        }

        if (transceiver.rtpSender) {
            var trackId = transceiver.rtpSender._initialTrackId ||
                transceiver.rtpSender.track.id;
            transceiver.rtpSender._initialTrackId = trackId;
            // spec.
            var msid = 'msid:' + (stream ? stream.id : '-') + ' ' +
                trackId + '\r\n';
            sdp$1 += 'a=' + msid;
            // for Chrome. Legacy should no longer be required.
            sdp$1 += 'a=ssrc:' + transceiver.sendEncodingParameters[0].ssrc +
                ' ' + msid;

            // RTX
            if (transceiver.sendEncodingParameters[0].rtx) {
                sdp$1 += 'a=ssrc:' + transceiver.sendEncodingParameters[0].rtx.ssrc +
                    ' ' + msid;
                sdp$1 += 'a=ssrc-group:FID ' +
                    transceiver.sendEncodingParameters[0].ssrc + ' ' +
                    transceiver.sendEncodingParameters[0].rtx.ssrc +
                    '\r\n';
            }
        }
        // FIXME: this should be written by writeRtpDescription.
        sdp$1 += 'a=ssrc:' + transceiver.sendEncodingParameters[0].ssrc +
            ' cname:' + sdp.localCName + '\r\n';
        if (transceiver.rtpSender && transceiver.sendEncodingParameters[0].rtx) {
            sdp$1 += 'a=ssrc:' + transceiver.sendEncodingParameters[0].rtx.ssrc +
                ' cname:' + sdp.localCName + '\r\n';
        }
        return sdp$1;
    }

    // Edge does not like
    // 1) stun: filtered after 14393 unless ?transport=udp is present
    // 2) turn: that does not have all of turn:host:port?transport=udp
    // 3) turn: with ipv6 addresses
    // 4) turn: occurring muliple times
    function filterIceServers(iceServers, edgeVersion) {
        var hasTurn = false;
        iceServers = JSON.parse(JSON.stringify(iceServers));
        return iceServers.filter(function (server) {
            if (server && (server.urls || server.url)) {
                var urls = server.urls || server.url;
                if (server.url && !server.urls) {
                    console.warn('RTCIceServer.url is deprecated! Use urls instead.');
                }
                var isString = typeof urls === 'string';
                if (isString) {
                    urls = [urls];
                }
                urls = urls.filter(function (url) {
                    var validTurn = url.indexOf('turn:') === 0 &&
                        url.indexOf('transport=udp') !== -1 &&
                        url.indexOf('turn:[') === -1 &&
                        !hasTurn;

                    if (validTurn) {
                        hasTurn = true;
                        return true;
                    }
                    return url.indexOf('stun:') === 0 && edgeVersion >= 14393 &&
                        url.indexOf('?transport=udp') === -1;
                });

                delete server.url;
                server.urls = isString ? urls[0] : urls;
                return !!urls.length;
            }
        });
    }

    // Determines the intersection of local and remote capabilities.
    function getCommonCapabilities(localCapabilities, remoteCapabilities) {
        var commonCapabilities = {
            codecs: [],
            headerExtensions: [],
            fecMechanisms: []
        };

        var findCodecByPayloadType = function (pt, codecs) {
            pt = parseInt(pt, 10);
            for (var i = 0; i < codecs.length; i++) {
                if (codecs[i].payloadType === pt ||
                    codecs[i].preferredPayloadType === pt) {
                    return codecs[i];
                }
            }
        };

        var rtxCapabilityMatches = function (lRtx, rRtx, lCodecs, rCodecs) {
            var lCodec = findCodecByPayloadType(lRtx.parameters.apt, lCodecs);
            var rCodec = findCodecByPayloadType(rRtx.parameters.apt, rCodecs);
            return lCodec && rCodec &&
                lCodec.name.toLowerCase() === rCodec.name.toLowerCase();
        };

        localCapabilities.codecs.forEach(function (lCodec) {
            for (var i = 0; i < remoteCapabilities.codecs.length; i++) {
                var rCodec = remoteCapabilities.codecs[i];
                if (lCodec.name.toLowerCase() === rCodec.name.toLowerCase() &&
                    lCodec.clockRate === rCodec.clockRate) {
                    if (lCodec.name.toLowerCase() === 'rtx' &&
                        lCodec.parameters && rCodec.parameters.apt) {
                        // for RTX we need to find the local rtx that has a apt
                        // which points to the same local codec as the remote one.
                        if (!rtxCapabilityMatches(lCodec, rCodec,
                            localCapabilities.codecs, remoteCapabilities.codecs)) {
                            continue;
                        }
                    }
                    rCodec = JSON.parse(JSON.stringify(rCodec)); // deepcopy
                    // number of channels is the highest common number of channels
                    rCodec.numChannels = Math.min(lCodec.numChannels,
                        rCodec.numChannels);
                    // push rCodec so we reply with offerer payload type
                    commonCapabilities.codecs.push(rCodec);

                    // determine common feedback mechanisms
                    rCodec.rtcpFeedback = rCodec.rtcpFeedback.filter(function (fb) {
                        for (var j = 0; j < lCodec.rtcpFeedback.length; j++) {
                            if (lCodec.rtcpFeedback[j].type === fb.type &&
                                lCodec.rtcpFeedback[j].parameter === fb.parameter) {
                                return true;
                            }
                        }
                        return false;
                    });
                    // FIXME: also need to determine .parameters
                    //  see https://github.com/openpeer/ortc/issues/569
                    break;
                }
            }
        });

        localCapabilities.headerExtensions.forEach(function (lHeaderExtension) {
            for (var i = 0; i < remoteCapabilities.headerExtensions.length;
                 i++) {
                var rHeaderExtension = remoteCapabilities.headerExtensions[i];
                if (lHeaderExtension.uri === rHeaderExtension.uri) {
                    commonCapabilities.headerExtensions.push(rHeaderExtension);
                    break;
                }
            }
        });

        // FIXME: fecMechanisms
        return commonCapabilities;
    }

    // is action=setLocalDescription with type allowed in signalingState
    function isActionAllowedInSignalingState(action, type, signalingState) {
        return {
            offer: {
                setLocalDescription: ['stable', 'have-local-offer'],
                setRemoteDescription: ['stable', 'have-remote-offer']
            },
            answer: {
                setLocalDescription: ['have-remote-offer', 'have-local-pranswer'],
                setRemoteDescription: ['have-local-offer', 'have-remote-pranswer']
            }
        }[type][action].indexOf(signalingState) !== -1;
    }

    function maybeAddCandidate(iceTransport, candidate) {
        // Edge's internal representation adds some fields therefore
        // not all fieldѕ are taken into account.
        var alreadyAdded = iceTransport.getRemoteCandidates()
            .find(function (remoteCandidate) {
                return candidate.foundation === remoteCandidate.foundation &&
                    candidate.ip === remoteCandidate.ip &&
                    candidate.port === remoteCandidate.port &&
                    candidate.priority === remoteCandidate.priority &&
                    candidate.protocol === remoteCandidate.protocol &&
                    candidate.type === remoteCandidate.type;
            });
        if (!alreadyAdded) {
            iceTransport.addRemoteCandidate(candidate);
        }
        return !alreadyAdded;
    }


    function makeError(name, description) {
        var e = new Error(description);
        e.name = name;
        // legacy error codes from https://heycam.github.io/webidl/#idl-DOMException-error-names
        e.code = {
            NotSupportedError: 9,
            InvalidStateError: 11,
            InvalidAccessError: 15,
            TypeError: undefined,
            OperationError: undefined
        }[name];
        return e;
    }

    var rtcpeerconnection = function (window, edgeVersion) {
        // https://w3c.github.io/mediacapture-main/#mediastream
        // Helper function to add the track to the stream and
        // dispatch the event ourselves.
        function addTrackToStreamAndFireEvent(track, stream) {
            stream.addTrack(track);
            stream.dispatchEvent(new window.MediaStreamTrackEvent('addtrack',
                {track: track}));
        }

        function removeTrackFromStreamAndFireEvent(track, stream) {
            stream.removeTrack(track);
            stream.dispatchEvent(new window.MediaStreamTrackEvent('removetrack',
                {track: track}));
        }

        function fireAddTrack(pc, track, receiver, streams) {
            var trackEvent = new Event('track');
            trackEvent.track = track;
            trackEvent.receiver = receiver;
            trackEvent.transceiver = {receiver: receiver};
            trackEvent.streams = streams;
            window.setTimeout(function () {
                pc._dispatchEvent('track', trackEvent);
            });
        }

        var RTCPeerConnection = function (config) {
            var pc = this;

            var _eventTarget = document.createDocumentFragment();
            ['addEventListener', 'removeEventListener', 'dispatchEvent']
                .forEach(function (method) {
                    pc[method] = _eventTarget[method].bind(_eventTarget);
                });

            this.canTrickleIceCandidates = null;

            this.needNegotiation = false;

            this.localStreams = [];
            this.remoteStreams = [];

            this._localDescription = null;
            this._remoteDescription = null;

            this.signalingState = 'stable';
            this.iceConnectionState = 'new';
            this.connectionState = 'new';
            this.iceGatheringState = 'new';

            config = JSON.parse(JSON.stringify(config || {}));

            this.usingBundle = config.bundlePolicy === 'max-bundle';
            if (config.rtcpMuxPolicy === 'negotiate') {
                throw(makeError('NotSupportedError',
                    'rtcpMuxPolicy \'negotiate\' is not supported'));
            } else if (!config.rtcpMuxPolicy) {
                config.rtcpMuxPolicy = 'require';
            }

            switch (config.iceTransportPolicy) {
                case 'all':
                case 'relay':
                    break;
                default:
                    config.iceTransportPolicy = 'all';
                    break;
            }

            switch (config.bundlePolicy) {
                case 'balanced':
                case 'max-compat':
                case 'max-bundle':
                    break;
                default:
                    config.bundlePolicy = 'balanced';
                    break;
            }

            config.iceServers = filterIceServers(config.iceServers || [], edgeVersion);

            this._iceGatherers = [];
            if (config.iceCandidatePoolSize) {
                for (var i = config.iceCandidatePoolSize; i > 0; i--) {
                    this._iceGatherers.push(new window.RTCIceGatherer({
                        iceServers: config.iceServers,
                        gatherPolicy: config.iceTransportPolicy
                    }));
                }
            } else {
                config.iceCandidatePoolSize = 0;
            }

            this._config = config;

            // per-track iceGathers, iceTransports, dtlsTransports, rtpSenders, ...
            // everything that is needed to describe a SDP m-line.
            this.transceivers = [];

            this._sdpSessionId = sdp.generateSessionId();
            this._sdpSessionVersion = 0;

            this._dtlsRole = undefined; // role for a=setup to use in answers.

            this._isClosed = false;
        };

        Object.defineProperty(RTCPeerConnection.prototype, 'localDescription', {
            configurable: true,
            get: function () {
                return this._localDescription;
            }
        });
        Object.defineProperty(RTCPeerConnection.prototype, 'remoteDescription', {
            configurable: true,
            get: function () {
                return this._remoteDescription;
            }
        });

        // set up event handlers on prototype
        RTCPeerConnection.prototype.onicecandidate = null;
        RTCPeerConnection.prototype.onaddstream = null;
        RTCPeerConnection.prototype.ontrack = null;
        RTCPeerConnection.prototype.onremovestream = null;
        RTCPeerConnection.prototype.onsignalingstatechange = null;
        RTCPeerConnection.prototype.oniceconnectionstatechange = null;
        RTCPeerConnection.prototype.onconnectionstatechange = null;
        RTCPeerConnection.prototype.onicegatheringstatechange = null;
        RTCPeerConnection.prototype.onnegotiationneeded = null;
        RTCPeerConnection.prototype.ondatachannel = null;

        RTCPeerConnection.prototype._dispatchEvent = function (name, event) {
            if (this._isClosed) {
                return;
            }
            this.dispatchEvent(event);
            if (typeof this['on' + name] === 'function') {
                this['on' + name](event);
            }
        };

        RTCPeerConnection.prototype._emitGatheringStateChange = function () {
            var event = new Event('icegatheringstatechange');
            this._dispatchEvent('icegatheringstatechange', event);
        };

        RTCPeerConnection.prototype.getConfiguration = function () {
            return this._config;
        };

        RTCPeerConnection.prototype.getLocalStreams = function () {
            return this.localStreams;
        };

        RTCPeerConnection.prototype.getRemoteStreams = function () {
            return this.remoteStreams;
        };

        // internal helper to create a transceiver object.
        // (which is not yet the same as the WebRTC 1.0 transceiver)
        RTCPeerConnection.prototype._createTransceiver = function (kind, doNotAdd) {
            var hasBundleTransport = this.transceivers.length > 0;
            var transceiver = {
                track: null,
                iceGatherer: null,
                iceTransport: null,
                dtlsTransport: null,
                localCapabilities: null,
                remoteCapabilities: null,
                rtpSender: null,
                rtpReceiver: null,
                kind: kind,
                mid: null,
                sendEncodingParameters: null,
                recvEncodingParameters: null,
                stream: null,
                associatedRemoteMediaStreams: [],
                wantReceive: true
            };
            if (this.usingBundle && hasBundleTransport) {
                transceiver.iceTransport = this.transceivers[0].iceTransport;
                transceiver.dtlsTransport = this.transceivers[0].dtlsTransport;
            } else {
                var transports = this._createIceAndDtlsTransports();
                transceiver.iceTransport = transports.iceTransport;
                transceiver.dtlsTransport = transports.dtlsTransport;
            }
            if (!doNotAdd) {
                this.transceivers.push(transceiver);
            }
            return transceiver;
        };

        RTCPeerConnection.prototype.addTrack = function (track, stream) {
            if (this._isClosed) {
                throw makeError('InvalidStateError',
                    'Attempted to call addTrack on a closed peerconnection.');
            }

            var alreadyExists = this.transceivers.find(function (s) {
                return s.track === track;
            });

            if (alreadyExists) {
                throw makeError('InvalidAccessError', 'Track already exists.');
            }

            var transceiver;
            for (var i = 0; i < this.transceivers.length; i++) {
                if (!this.transceivers[i].track &&
                    this.transceivers[i].kind === track.kind) {
                    transceiver = this.transceivers[i];
                }
            }
            if (!transceiver) {
                transceiver = this._createTransceiver(track.kind);
            }

            this._maybeFireNegotiationNeeded();

            if (this.localStreams.indexOf(stream) === -1) {
                this.localStreams.push(stream);
            }

            transceiver.track = track;
            transceiver.stream = stream;
            transceiver.rtpSender = new window.RTCRtpSender(track,
                transceiver.dtlsTransport);
            return transceiver.rtpSender;
        };

        RTCPeerConnection.prototype.addStream = function (stream) {
            var pc = this;
            if (edgeVersion >= 15025) {
                stream.getTracks().forEach(function (track) {
                    pc.addTrack(track, stream);
                });
            } else {
                // Clone is necessary for local demos mostly, attaching directly
                // to two different senders does not work (build 10547).
                // Fixed in 15025 (or earlier)
                var clonedStream = stream.clone();
                stream.getTracks().forEach(function (track, idx) {
                    var clonedTrack = clonedStream.getTracks()[idx];
                    track.addEventListener('enabled', function (event) {
                        clonedTrack.enabled = event.enabled;
                    });
                });
                clonedStream.getTracks().forEach(function (track) {
                    pc.addTrack(track, clonedStream);
                });
            }
        };

        RTCPeerConnection.prototype.removeTrack = function (sender) {
            if (this._isClosed) {
                throw makeError('InvalidStateError',
                    'Attempted to call removeTrack on a closed peerconnection.');
            }

            if (!(sender instanceof window.RTCRtpSender)) {
                throw new TypeError('Argument 1 of RTCPeerConnection.removeTrack ' +
                    'does not implement interface RTCRtpSender.');
            }

            var transceiver = this.transceivers.find(function (t) {
                return t.rtpSender === sender;
            });

            if (!transceiver) {
                throw makeError('InvalidAccessError',
                    'Sender was not created by this connection.');
            }
            var stream = transceiver.stream;

            transceiver.rtpSender.stop();
            transceiver.rtpSender = null;
            transceiver.track = null;
            transceiver.stream = null;

            // remove the stream from the set of local streams
            var localStreams = this.transceivers.map(function (t) {
                return t.stream;
            });
            if (localStreams.indexOf(stream) === -1 &&
                this.localStreams.indexOf(stream) > -1) {
                this.localStreams.splice(this.localStreams.indexOf(stream), 1);
            }

            this._maybeFireNegotiationNeeded();
        };

        RTCPeerConnection.prototype.removeStream = function (stream) {
            var pc = this;
            stream.getTracks().forEach(function (track) {
                var sender = pc.getSenders().find(function (s) {
                    return s.track === track;
                });
                if (sender) {
                    pc.removeTrack(sender);
                }
            });
        };

        RTCPeerConnection.prototype.getSenders = function () {
            return this.transceivers.filter(function (transceiver) {
                return !!transceiver.rtpSender;
            })
                .map(function (transceiver) {
                    return transceiver.rtpSender;
                });
        };

        RTCPeerConnection.prototype.getReceivers = function () {
            return this.transceivers.filter(function (transceiver) {
                return !!transceiver.rtpReceiver;
            })
                .map(function (transceiver) {
                    return transceiver.rtpReceiver;
                });
        };


        RTCPeerConnection.prototype._createIceGatherer = function (sdpMLineIndex,
                                                                   usingBundle) {
            var pc = this;
            if (usingBundle && sdpMLineIndex > 0) {
                return this.transceivers[0].iceGatherer;
            } else if (this._iceGatherers.length) {
                return this._iceGatherers.shift();
            }
            var iceGatherer = new window.RTCIceGatherer({
                iceServers: this._config.iceServers,
                gatherPolicy: this._config.iceTransportPolicy
            });
            Object.defineProperty(iceGatherer, 'state',
                {value: 'new', writable: true}
            );

            this.transceivers[sdpMLineIndex].bufferedCandidateEvents = [];
            this.transceivers[sdpMLineIndex].bufferCandidates = function (event) {
                var end = !event.candidate || Object.keys(event.candidate).length === 0;
                // polyfill since RTCIceGatherer.state is not implemented in
                // Edge 10547 yet.
                iceGatherer.state = end ? 'completed' : 'gathering';
                if (pc.transceivers[sdpMLineIndex].bufferedCandidateEvents !== null) {
                    pc.transceivers[sdpMLineIndex].bufferedCandidateEvents.push(event);
                }
            };
            iceGatherer.addEventListener('localcandidate',
                this.transceivers[sdpMLineIndex].bufferCandidates);
            return iceGatherer;
        };

        // start gathering from an RTCIceGatherer.
        RTCPeerConnection.prototype._gather = function (mid, sdpMLineIndex) {
            var pc = this;
            var iceGatherer = this.transceivers[sdpMLineIndex].iceGatherer;
            if (iceGatherer.onlocalcandidate) {
                return;
            }
            var bufferedCandidateEvents =
                this.transceivers[sdpMLineIndex].bufferedCandidateEvents;
            this.transceivers[sdpMLineIndex].bufferedCandidateEvents = null;
            iceGatherer.removeEventListener('localcandidate',
                this.transceivers[sdpMLineIndex].bufferCandidates);
            iceGatherer.onlocalcandidate = function (evt) {
                if (pc.usingBundle && sdpMLineIndex > 0) {
                    // if we know that we use bundle we can drop candidates with
                    // ѕdpMLineIndex > 0. If we don't do this then our state gets
                    // confused since we dispose the extra ice gatherer.
                    return;
                }
                var event = new Event('icecandidate');
                event.candidate = {sdpMid: mid, sdpMLineIndex: sdpMLineIndex};

                var cand = evt.candidate;
                // Edge emits an empty object for RTCIceCandidateComplete‥
                var end = !cand || Object.keys(cand).length === 0;
                if (end) {
                    // polyfill since RTCIceGatherer.state is not implemented in
                    // Edge 10547 yet.
                    if (iceGatherer.state === 'new' || iceGatherer.state === 'gathering') {
                        iceGatherer.state = 'completed';
                    }
                } else {
                    if (iceGatherer.state === 'new') {
                        iceGatherer.state = 'gathering';
                    }
                    // RTCIceCandidate doesn't have a component, needs to be added
                    cand.component = 1;
                    // also the usernameFragment. TODO: update SDP to take both variants.
                    cand.ufrag = iceGatherer.getLocalParameters().usernameFragment;

                    var serializedCandidate = sdp.writeCandidate(cand);
                    event.candidate = Object.assign(event.candidate,
                        sdp.parseCandidate(serializedCandidate));

                    event.candidate.candidate = serializedCandidate;
                    event.candidate.toJSON = function () {
                        return {
                            candidate: event.candidate.candidate,
                            sdpMid: event.candidate.sdpMid,
                            sdpMLineIndex: event.candidate.sdpMLineIndex,
                            usernameFragment: event.candidate.usernameFragment
                        };
                    };
                }

                // update local description.
                var sections = sdp.getMediaSections(pc._localDescription.sdp);
                if (!end) {
                    sections[event.candidate.sdpMLineIndex] +=
                        'a=' + event.candidate.candidate + '\r\n';
                } else {
                    sections[event.candidate.sdpMLineIndex] +=
                        'a=end-of-candidates\r\n';
                }
                pc._localDescription.sdp =
                    sdp.getDescription(pc._localDescription.sdp) +
                    sections.join('');
                var complete = pc.transceivers.every(function (transceiver) {
                    return transceiver.iceGatherer &&
                        transceiver.iceGatherer.state === 'completed';
                });

                if (pc.iceGatheringState !== 'gathering') {
                    pc.iceGatheringState = 'gathering';
                    pc._emitGatheringStateChange();
                }

                // Emit candidate. Also emit null candidate when all gatherers are
                // complete.
                if (!end) {
                    pc._dispatchEvent('icecandidate', event);
                }
                if (complete) {
                    pc._dispatchEvent('icecandidate', new Event('icecandidate'));
                    pc.iceGatheringState = 'complete';
                    pc._emitGatheringStateChange();
                }
            };

            // emit already gathered candidates.
            window.setTimeout(function () {
                bufferedCandidateEvents.forEach(function (e) {
                    iceGatherer.onlocalcandidate(e);
                });
            }, 0);
        };

        // Create ICE transport and DTLS transport.
        RTCPeerConnection.prototype._createIceAndDtlsTransports = function () {
            var pc = this;
            var iceTransport = new window.RTCIceTransport(null);
            iceTransport.onicestatechange = function () {
                pc._updateIceConnectionState();
                pc._updateConnectionState();
            };

            var dtlsTransport = new window.RTCDtlsTransport(iceTransport);
            dtlsTransport.ondtlsstatechange = function () {
                pc._updateConnectionState();
            };
            dtlsTransport.onerror = function () {
                // onerror does not set state to failed by itself.
                Object.defineProperty(dtlsTransport, 'state',
                    {value: 'failed', writable: true});
                pc._updateConnectionState();
            };

            return {
                iceTransport: iceTransport,
                dtlsTransport: dtlsTransport
            };
        };

        // Destroy ICE gatherer, ICE transport and DTLS transport.
        // Without triggering the callbacks.
        RTCPeerConnection.prototype._disposeIceAndDtlsTransports = function (
            sdpMLineIndex) {
            var iceGatherer = this.transceivers[sdpMLineIndex].iceGatherer;
            if (iceGatherer) {
                delete iceGatherer.onlocalcandidate;
                delete this.transceivers[sdpMLineIndex].iceGatherer;
            }
            var iceTransport = this.transceivers[sdpMLineIndex].iceTransport;
            if (iceTransport) {
                delete iceTransport.onicestatechange;
                delete this.transceivers[sdpMLineIndex].iceTransport;
            }
            var dtlsTransport = this.transceivers[sdpMLineIndex].dtlsTransport;
            if (dtlsTransport) {
                delete dtlsTransport.ondtlsstatechange;
                delete dtlsTransport.onerror;
                delete this.transceivers[sdpMLineIndex].dtlsTransport;
            }
        };

        // Start the RTP Sender and Receiver for a transceiver.
        RTCPeerConnection.prototype._transceive = function (transceiver,
                                                            send, recv) {
            var params = getCommonCapabilities(transceiver.localCapabilities,
                transceiver.remoteCapabilities);
            if (send && transceiver.rtpSender) {
                params.encodings = transceiver.sendEncodingParameters;
                params.rtcp = {
                    cname: sdp.localCName,
                    compound: transceiver.rtcpParameters.compound
                };
                if (transceiver.recvEncodingParameters.length) {
                    params.rtcp.ssrc = transceiver.recvEncodingParameters[0].ssrc;
                }
                transceiver.rtpSender.send(params);
            }
            if (recv && transceiver.rtpReceiver && params.codecs.length > 0) {
                // remove RTX field in Edge 14942
                if (transceiver.kind === 'video'
                    && transceiver.recvEncodingParameters
                    && edgeVersion < 15019) {
                    transceiver.recvEncodingParameters.forEach(function (p) {
                        delete p.rtx;
                    });
                }
                if (transceiver.recvEncodingParameters.length) {
                    params.encodings = transceiver.recvEncodingParameters;
                } else {
                    params.encodings = [{}];
                }
                params.rtcp = {
                    compound: transceiver.rtcpParameters.compound
                };
                if (transceiver.rtcpParameters.cname) {
                    params.rtcp.cname = transceiver.rtcpParameters.cname;
                }
                if (transceiver.sendEncodingParameters.length) {
                    params.rtcp.ssrc = transceiver.sendEncodingParameters[0].ssrc;
                }
                transceiver.rtpReceiver.receive(params);
            }
        };

        RTCPeerConnection.prototype.setLocalDescription = function (description) {
            var pc = this;

            // Note: pranswer is not supported.
            if (['offer', 'answer'].indexOf(description.type) === -1) {
                return Promise.reject(makeError('TypeError',
                    'Unsupported type "' + description.type + '"'));
            }

            if (!isActionAllowedInSignalingState('setLocalDescription',
                description.type, pc.signalingState) || pc._isClosed) {
                return Promise.reject(makeError('InvalidStateError',
                    'Can not set local ' + description.type +
                    ' in state ' + pc.signalingState));
            }

            var sections;
            var sessionpart;
            if (description.type === 'offer') {
                // VERY limited support for SDP munging. Limited to:
                // * changing the order of codecs
                sections = sdp.splitSections(description.sdp);
                sessionpart = sections.shift();
                sections.forEach(function (mediaSection, sdpMLineIndex) {
                    var caps = sdp.parseRtpParameters(mediaSection);
                    pc.transceivers[sdpMLineIndex].localCapabilities = caps;
                });

                pc.transceivers.forEach(function (transceiver, sdpMLineIndex) {
                    pc._gather(transceiver.mid, sdpMLineIndex);
                });
            } else if (description.type === 'answer') {
                sections = sdp.splitSections(pc._remoteDescription.sdp);
                sessionpart = sections.shift();
                var isIceLite = sdp.matchPrefix(sessionpart,
                    'a=ice-lite').length > 0;
                sections.forEach(function (mediaSection, sdpMLineIndex) {
                    var transceiver = pc.transceivers[sdpMLineIndex];
                    var iceGatherer = transceiver.iceGatherer;
                    var iceTransport = transceiver.iceTransport;
                    var dtlsTransport = transceiver.dtlsTransport;
                    var localCapabilities = transceiver.localCapabilities;
                    var remoteCapabilities = transceiver.remoteCapabilities;

                    // treat bundle-only as not-rejected.
                    var rejected = sdp.isRejected(mediaSection) &&
                        sdp.matchPrefix(mediaSection, 'a=bundle-only').length === 0;

                    if (!rejected && !transceiver.rejected) {
                        var remoteIceParameters = sdp.getIceParameters(
                            mediaSection, sessionpart);
                        var remoteDtlsParameters = sdp.getDtlsParameters(
                            mediaSection, sessionpart);
                        if (isIceLite) {
                            remoteDtlsParameters.role = 'server';
                        }

                        if (!pc.usingBundle || sdpMLineIndex === 0) {
                            pc._gather(transceiver.mid, sdpMLineIndex);
                            if (iceTransport.state === 'new') {
                                iceTransport.start(iceGatherer, remoteIceParameters,
                                    isIceLite ? 'controlling' : 'controlled');
                            }
                            if (dtlsTransport.state === 'new') {
                                dtlsTransport.start(remoteDtlsParameters);
                            }
                        }

                        // Calculate intersection of capabilities.
                        var params = getCommonCapabilities(localCapabilities,
                            remoteCapabilities);

                        // Start the RTCRtpSender. The RTCRtpReceiver for this
                        // transceiver has already been started in setRemoteDescription.
                        pc._transceive(transceiver,
                            params.codecs.length > 0,
                            false);
                    }
                });
            }

            pc._localDescription = {
                type: description.type,
                sdp: description.sdp
            };
            if (description.type === 'offer') {
                pc._updateSignalingState('have-local-offer');
            } else {
                pc._updateSignalingState('stable');
            }

            return Promise.resolve();
        };

        RTCPeerConnection.prototype.setRemoteDescription = function (description) {
            var pc = this;

            // Note: pranswer is not supported.
            if (['offer', 'answer'].indexOf(description.type) === -1) {
                return Promise.reject(makeError('TypeError',
                    'Unsupported type "' + description.type + '"'));
            }

            if (!isActionAllowedInSignalingState('setRemoteDescription',
                description.type, pc.signalingState) || pc._isClosed) {
                return Promise.reject(makeError('InvalidStateError',
                    'Can not set remote ' + description.type +
                    ' in state ' + pc.signalingState));
            }

            var streams = {};
            pc.remoteStreams.forEach(function (stream) {
                streams[stream.id] = stream;
            });
            var receiverList = [];
            var sections = sdp.splitSections(description.sdp);
            var sessionpart = sections.shift();
            var isIceLite = sdp.matchPrefix(sessionpart,
                'a=ice-lite').length > 0;
            var usingBundle = sdp.matchPrefix(sessionpart,
                'a=group:BUNDLE ').length > 0;
            pc.usingBundle = usingBundle;
            var iceOptions = sdp.matchPrefix(sessionpart,
                'a=ice-options:')[0];
            if (iceOptions) {
                pc.canTrickleIceCandidates = iceOptions.substr(14).split(' ')
                    .indexOf('trickle') >= 0;
            } else {
                pc.canTrickleIceCandidates = false;
            }

            sections.forEach(function (mediaSection, sdpMLineIndex) {
                var lines = sdp.splitLines(mediaSection);
                var kind = sdp.getKind(mediaSection);
                // treat bundle-only as not-rejected.
                var rejected = sdp.isRejected(mediaSection) &&
                    sdp.matchPrefix(mediaSection, 'a=bundle-only').length === 0;
                var protocol = lines[0].substr(2).split(' ')[2];

                var direction = sdp.getDirection(mediaSection, sessionpart);
                var remoteMsid = sdp.parseMsid(mediaSection);

                var mid = sdp.getMid(mediaSection) || sdp.generateIdentifier();

                // Reject datachannels which are not implemented yet.
                if (rejected || (kind === 'application' && (protocol === 'DTLS/SCTP' ||
                    protocol === 'UDP/DTLS/SCTP'))) {
                    // TODO: this is dangerous in the case where a non-rejected m-line
                    //     becomes rejected.
                    pc.transceivers[sdpMLineIndex] = {
                        mid: mid,
                        kind: kind,
                        protocol: protocol,
                        rejected: true
                    };
                    return;
                }

                if (!rejected && pc.transceivers[sdpMLineIndex] &&
                    pc.transceivers[sdpMLineIndex].rejected) {
                    // recycle a rejected transceiver.
                    pc.transceivers[sdpMLineIndex] = pc._createTransceiver(kind, true);
                }

                var transceiver;
                var iceGatherer;
                var iceTransport;
                var dtlsTransport;
                var rtpReceiver;
                var sendEncodingParameters;
                var recvEncodingParameters;
                var localCapabilities;

                var track;
                // FIXME: ensure the mediaSection has rtcp-mux set.
                var remoteCapabilities = sdp.parseRtpParameters(mediaSection);
                var remoteIceParameters;
                var remoteDtlsParameters;
                if (!rejected) {
                    remoteIceParameters = sdp.getIceParameters(mediaSection,
                        sessionpart);
                    remoteDtlsParameters = sdp.getDtlsParameters(mediaSection,
                        sessionpart);
                    remoteDtlsParameters.role = 'client';
                }
                recvEncodingParameters =
                    sdp.parseRtpEncodingParameters(mediaSection);

                var rtcpParameters = sdp.parseRtcpParameters(mediaSection);

                var isComplete = sdp.matchPrefix(mediaSection,
                    'a=end-of-candidates', sessionpart).length > 0;
                var cands = sdp.matchPrefix(mediaSection, 'a=candidate:')
                    .map(function (cand) {
                        return sdp.parseCandidate(cand);
                    })
                    .filter(function (cand) {
                        return cand.component === 1;
                    });

                // Check if we can use BUNDLE and dispose transports.
                if ((description.type === 'offer' || description.type === 'answer') &&
                    !rejected && usingBundle && sdpMLineIndex > 0 &&
                    pc.transceivers[sdpMLineIndex]) {
                    pc._disposeIceAndDtlsTransports(sdpMLineIndex);
                    pc.transceivers[sdpMLineIndex].iceGatherer =
                        pc.transceivers[0].iceGatherer;
                    pc.transceivers[sdpMLineIndex].iceTransport =
                        pc.transceivers[0].iceTransport;
                    pc.transceivers[sdpMLineIndex].dtlsTransport =
                        pc.transceivers[0].dtlsTransport;
                    if (pc.transceivers[sdpMLineIndex].rtpSender) {
                        pc.transceivers[sdpMLineIndex].rtpSender.setTransport(
                            pc.transceivers[0].dtlsTransport);
                    }
                    if (pc.transceivers[sdpMLineIndex].rtpReceiver) {
                        pc.transceivers[sdpMLineIndex].rtpReceiver.setTransport(
                            pc.transceivers[0].dtlsTransport);
                    }
                }
                if (description.type === 'offer' && !rejected) {
                    transceiver = pc.transceivers[sdpMLineIndex] ||
                        pc._createTransceiver(kind);
                    transceiver.mid = mid;

                    if (!transceiver.iceGatherer) {
                        transceiver.iceGatherer = pc._createIceGatherer(sdpMLineIndex,
                            usingBundle);
                    }

                    if (cands.length && transceiver.iceTransport.state === 'new') {
                        if (isComplete && (!usingBundle || sdpMLineIndex === 0)) {
                            transceiver.iceTransport.setRemoteCandidates(cands);
                        } else {
                            cands.forEach(function (candidate) {
                                maybeAddCandidate(transceiver.iceTransport, candidate);
                            });
                        }
                    }

                    localCapabilities = window.RTCRtpReceiver.getCapabilities(kind);

                    // filter RTX until additional stuff needed for RTX is implemented
                    // in adapter.js
                    if (edgeVersion < 15019) {
                        localCapabilities.codecs = localCapabilities.codecs.filter(
                            function (codec) {
                                return codec.name !== 'rtx';
                            });
                    }

                    sendEncodingParameters = transceiver.sendEncodingParameters || [{
                        ssrc: (2 * sdpMLineIndex + 2) * 1001
                    }];

                    // TODO: rewrite to use http://w3c.github.io/webrtc-pc/#set-associated-remote-streams
                    var isNewTrack = false;
                    if (direction === 'sendrecv' || direction === 'sendonly') {
                        isNewTrack = !transceiver.rtpReceiver;
                        rtpReceiver = transceiver.rtpReceiver ||
                            new window.RTCRtpReceiver(transceiver.dtlsTransport, kind);

                        if (isNewTrack) {
                            var stream;
                            track = rtpReceiver.track;
                            // FIXME: does not work with Plan B.
                            if (remoteMsid && remoteMsid.stream === '-') ; else if (remoteMsid) {
                                if (!streams[remoteMsid.stream]) {
                                    streams[remoteMsid.stream] = new window.MediaStream();
                                    Object.defineProperty(streams[remoteMsid.stream], 'id', {
                                        get: function () {
                                            return remoteMsid.stream;
                                        }
                                    });
                                }
                                Object.defineProperty(track, 'id', {
                                    get: function () {
                                        return remoteMsid.track;
                                    }
                                });
                                stream = streams[remoteMsid.stream];
                            } else {
                                if (!streams.default) {
                                    streams.default = new window.MediaStream();
                                }
                                stream = streams.default;
                            }
                            if (stream) {
                                addTrackToStreamAndFireEvent(track, stream);
                                transceiver.associatedRemoteMediaStreams.push(stream);
                            }
                            receiverList.push([track, rtpReceiver, stream]);
                        }
                    } else if (transceiver.rtpReceiver && transceiver.rtpReceiver.track) {
                        transceiver.associatedRemoteMediaStreams.forEach(function (s) {
                            var nativeTrack = s.getTracks().find(function (t) {
                                return t.id === transceiver.rtpReceiver.track.id;
                            });
                            if (nativeTrack) {
                                removeTrackFromStreamAndFireEvent(nativeTrack, s);
                            }
                        });
                        transceiver.associatedRemoteMediaStreams = [];
                    }

                    transceiver.localCapabilities = localCapabilities;
                    transceiver.remoteCapabilities = remoteCapabilities;
                    transceiver.rtpReceiver = rtpReceiver;
                    transceiver.rtcpParameters = rtcpParameters;
                    transceiver.sendEncodingParameters = sendEncodingParameters;
                    transceiver.recvEncodingParameters = recvEncodingParameters;

                    // Start the RTCRtpReceiver now. The RTPSender is started in
                    // setLocalDescription.
                    pc._transceive(pc.transceivers[sdpMLineIndex],
                        false,
                        isNewTrack);
                } else if (description.type === 'answer' && !rejected) {
                    transceiver = pc.transceivers[sdpMLineIndex];
                    iceGatherer = transceiver.iceGatherer;
                    iceTransport = transceiver.iceTransport;
                    dtlsTransport = transceiver.dtlsTransport;
                    rtpReceiver = transceiver.rtpReceiver;
                    sendEncodingParameters = transceiver.sendEncodingParameters;
                    localCapabilities = transceiver.localCapabilities;

                    pc.transceivers[sdpMLineIndex].recvEncodingParameters =
                        recvEncodingParameters;
                    pc.transceivers[sdpMLineIndex].remoteCapabilities =
                        remoteCapabilities;
                    pc.transceivers[sdpMLineIndex].rtcpParameters = rtcpParameters;

                    if (cands.length && iceTransport.state === 'new') {
                        if ((isIceLite || isComplete) &&
                            (!usingBundle || sdpMLineIndex === 0)) {
                            iceTransport.setRemoteCandidates(cands);
                        } else {
                            cands.forEach(function (candidate) {
                                maybeAddCandidate(transceiver.iceTransport, candidate);
                            });
                        }
                    }

                    if (!usingBundle || sdpMLineIndex === 0) {
                        if (iceTransport.state === 'new') {
                            iceTransport.start(iceGatherer, remoteIceParameters,
                                'controlling');
                        }
                        if (dtlsTransport.state === 'new') {
                            dtlsTransport.start(remoteDtlsParameters);
                        }
                    }

                    // If the offer contained RTX but the answer did not,
                    // remove RTX from sendEncodingParameters.
                    var commonCapabilities = getCommonCapabilities(
                        transceiver.localCapabilities,
                        transceiver.remoteCapabilities);

                    var hasRtx = commonCapabilities.codecs.filter(function (c) {
                        return c.name.toLowerCase() === 'rtx';
                    }).length;
                    if (!hasRtx && transceiver.sendEncodingParameters[0].rtx) {
                        delete transceiver.sendEncodingParameters[0].rtx;
                    }

                    pc._transceive(transceiver,
                        direction === 'sendrecv' || direction === 'recvonly',
                        direction === 'sendrecv' || direction === 'sendonly');

                    // TODO: rewrite to use http://w3c.github.io/webrtc-pc/#set-associated-remote-streams
                    if (rtpReceiver &&
                        (direction === 'sendrecv' || direction === 'sendonly')) {
                        track = rtpReceiver.track;
                        if (remoteMsid) {
                            if (!streams[remoteMsid.stream]) {
                                streams[remoteMsid.stream] = new window.MediaStream();
                            }
                            addTrackToStreamAndFireEvent(track, streams[remoteMsid.stream]);
                            receiverList.push([track, rtpReceiver, streams[remoteMsid.stream]]);
                        } else {
                            if (!streams.default) {
                                streams.default = new window.MediaStream();
                            }
                            addTrackToStreamAndFireEvent(track, streams.default);
                            receiverList.push([track, rtpReceiver, streams.default]);
                        }
                    } else {
                        // FIXME: actually the receiver should be created later.
                        delete transceiver.rtpReceiver;
                    }
                }
            });

            if (pc._dtlsRole === undefined) {
                pc._dtlsRole = description.type === 'offer' ? 'active' : 'passive';
            }

            pc._remoteDescription = {
                type: description.type,
                sdp: description.sdp
            };
            if (description.type === 'offer') {
                pc._updateSignalingState('have-remote-offer');
            } else {
                pc._updateSignalingState('stable');
            }
            Object.keys(streams).forEach(function (sid) {
                var stream = streams[sid];
                if (stream.getTracks().length) {
                    if (pc.remoteStreams.indexOf(stream) === -1) {
                        pc.remoteStreams.push(stream);
                        var event = new Event('addstream');
                        event.stream = stream;
                        window.setTimeout(function () {
                            pc._dispatchEvent('addstream', event);
                        });
                    }

                    receiverList.forEach(function (item) {
                        var track = item[0];
                        var receiver = item[1];
                        if (stream.id !== item[2].id) {
                            return;
                        }
                        fireAddTrack(pc, track, receiver, [stream]);
                    });
                }
            });
            receiverList.forEach(function (item) {
                if (item[2]) {
                    return;
                }
                fireAddTrack(pc, item[0], item[1], []);
            });

            // check whether addIceCandidate({}) was called within four seconds after
            // setRemoteDescription.
            window.setTimeout(function () {
                if (!(pc && pc.transceivers)) {
                    return;
                }
                pc.transceivers.forEach(function (transceiver) {
                    if (transceiver.iceTransport &&
                        transceiver.iceTransport.state === 'new' &&
                        transceiver.iceTransport.getRemoteCandidates().length > 0) {
                        console.warn('Timeout for addRemoteCandidate. Consider sending ' +
                            'an end-of-candidates notification');
                        transceiver.iceTransport.addRemoteCandidate({});
                    }
                });
            }, 4000);

            return Promise.resolve();
        };

        RTCPeerConnection.prototype.close = function () {
            this.transceivers.forEach(function (transceiver) {
                /* not yet
	      if (transceiver.iceGatherer) {
	        transceiver.iceGatherer.close();
	      }
	      */
                if (transceiver.iceTransport) {
                    transceiver.iceTransport.stop();
                }
                if (transceiver.dtlsTransport) {
                    transceiver.dtlsTransport.stop();
                }
                if (transceiver.rtpSender) {
                    transceiver.rtpSender.stop();
                }
                if (transceiver.rtpReceiver) {
                    transceiver.rtpReceiver.stop();
                }
            });
            // FIXME: clean up tracks, local streams, remote streams, etc
            this._isClosed = true;
            this._updateSignalingState('closed');
        };

        // Update the signaling state.
        RTCPeerConnection.prototype._updateSignalingState = function (newState) {
            this.signalingState = newState;
            var event = new Event('signalingstatechange');
            this._dispatchEvent('signalingstatechange', event);
        };

        // Determine whether to fire the negotiationneeded event.
        RTCPeerConnection.prototype._maybeFireNegotiationNeeded = function () {
            var pc = this;
            if (this.signalingState !== 'stable' || this.needNegotiation === true) {
                return;
            }
            this.needNegotiation = true;
            window.setTimeout(function () {
                if (pc.needNegotiation) {
                    pc.needNegotiation = false;
                    var event = new Event('negotiationneeded');
                    pc._dispatchEvent('negotiationneeded', event);
                }
            }, 0);
        };

        // Update the ice connection state.
        RTCPeerConnection.prototype._updateIceConnectionState = function () {
            var newState;
            var states = {
                'new': 0,
                closed: 0,
                checking: 0,
                connected: 0,
                completed: 0,
                disconnected: 0,
                failed: 0
            };
            this.transceivers.forEach(function (transceiver) {
                if (transceiver.iceTransport && !transceiver.rejected) {
                    states[transceiver.iceTransport.state]++;
                }
            });

            newState = 'new';
            if (states.failed > 0) {
                newState = 'failed';
            } else if (states.checking > 0) {
                newState = 'checking';
            } else if (states.disconnected > 0) {
                newState = 'disconnected';
            } else if (states.new > 0) {
                newState = 'new';
            } else if (states.connected > 0) {
                newState = 'connected';
            } else if (states.completed > 0) {
                newState = 'completed';
            }

            if (newState !== this.iceConnectionState) {
                this.iceConnectionState = newState;
                var event = new Event('iceconnectionstatechange');
                this._dispatchEvent('iceconnectionstatechange', event);
            }
        };

        // Update the connection state.
        RTCPeerConnection.prototype._updateConnectionState = function () {
            var newState;
            var states = {
                'new': 0,
                closed: 0,
                connecting: 0,
                connected: 0,
                completed: 0,
                disconnected: 0,
                failed: 0
            };
            this.transceivers.forEach(function (transceiver) {
                if (transceiver.iceTransport && transceiver.dtlsTransport &&
                    !transceiver.rejected) {
                    states[transceiver.iceTransport.state]++;
                    states[transceiver.dtlsTransport.state]++;
                }
            });
            // ICETransport.completed and connected are the same for this purpose.
            states.connected += states.completed;

            newState = 'new';
            if (states.failed > 0) {
                newState = 'failed';
            } else if (states.connecting > 0) {
                newState = 'connecting';
            } else if (states.disconnected > 0) {
                newState = 'disconnected';
            } else if (states.new > 0) {
                newState = 'new';
            } else if (states.connected > 0) {
                newState = 'connected';
            }

            if (newState !== this.connectionState) {
                this.connectionState = newState;
                var event = new Event('connectionstatechange');
                this._dispatchEvent('connectionstatechange', event);
            }
        };

        RTCPeerConnection.prototype.createOffer = function () {
            var pc = this;

            if (pc._isClosed) {
                return Promise.reject(makeError('InvalidStateError',
                    'Can not call createOffer after close'));
            }

            var numAudioTracks = pc.transceivers.filter(function (t) {
                return t.kind === 'audio';
            }).length;
            var numVideoTracks = pc.transceivers.filter(function (t) {
                return t.kind === 'video';
            }).length;

            // Determine number of audio and video tracks we need to send/recv.
            var offerOptions = arguments[0];
            if (offerOptions) {
                // Reject Chrome legacy constraints.
                if (offerOptions.mandatory || offerOptions.optional) {
                    throw new TypeError(
                        'Legacy mandatory/optional constraints not supported.');
                }
                if (offerOptions.offerToReceiveAudio !== undefined) {
                    if (offerOptions.offerToReceiveAudio === true) {
                        numAudioTracks = 1;
                    } else if (offerOptions.offerToReceiveAudio === false) {
                        numAudioTracks = 0;
                    } else {
                        numAudioTracks = offerOptions.offerToReceiveAudio;
                    }
                }
                if (offerOptions.offerToReceiveVideo !== undefined) {
                    if (offerOptions.offerToReceiveVideo === true) {
                        numVideoTracks = 1;
                    } else if (offerOptions.offerToReceiveVideo === false) {
                        numVideoTracks = 0;
                    } else {
                        numVideoTracks = offerOptions.offerToReceiveVideo;
                    }
                }
            }

            pc.transceivers.forEach(function (transceiver) {
                if (transceiver.kind === 'audio') {
                    numAudioTracks--;
                    if (numAudioTracks < 0) {
                        transceiver.wantReceive = false;
                    }
                } else if (transceiver.kind === 'video') {
                    numVideoTracks--;
                    if (numVideoTracks < 0) {
                        transceiver.wantReceive = false;
                    }
                }
            });

            // Create M-lines for recvonly streams.
            while (numAudioTracks > 0 || numVideoTracks > 0) {
                if (numAudioTracks > 0) {
                    pc._createTransceiver('audio');
                    numAudioTracks--;
                }
                if (numVideoTracks > 0) {
                    pc._createTransceiver('video');
                    numVideoTracks--;
                }
            }

            var sdp$1 = sdp.writeSessionBoilerplate(pc._sdpSessionId,
                pc._sdpSessionVersion++);
            pc.transceivers.forEach(function (transceiver, sdpMLineIndex) {
                // For each track, create an ice gatherer, ice transport,
                // dtls transport, potentially rtpsender and rtpreceiver.
                var track = transceiver.track;
                var kind = transceiver.kind;
                var mid = transceiver.mid || sdp.generateIdentifier();
                transceiver.mid = mid;

                if (!transceiver.iceGatherer) {
                    transceiver.iceGatherer = pc._createIceGatherer(sdpMLineIndex,
                        pc.usingBundle);
                }

                var localCapabilities = window.RTCRtpSender.getCapabilities(kind);
                // filter RTX until additional stuff needed for RTX is implemented
                // in adapter.js
                if (edgeVersion < 15019) {
                    localCapabilities.codecs = localCapabilities.codecs.filter(
                        function (codec) {
                            return codec.name !== 'rtx';
                        });
                }
                localCapabilities.codecs.forEach(function (codec) {
                    // work around https://bugs.chromium.org/p/webrtc/issues/detail?id=6552
                    // by adding level-asymmetry-allowed=1
                    if (codec.name === 'H264' &&
                        codec.parameters['level-asymmetry-allowed'] === undefined) {
                        codec.parameters['level-asymmetry-allowed'] = '1';
                    }

                    // for subsequent offers, we might have to re-use the payload
                    // type of the last offer.
                    if (transceiver.remoteCapabilities &&
                        transceiver.remoteCapabilities.codecs) {
                        transceiver.remoteCapabilities.codecs.forEach(function (remoteCodec) {
                            if (codec.name.toLowerCase() === remoteCodec.name.toLowerCase() &&
                                codec.clockRate === remoteCodec.clockRate) {
                                codec.preferredPayloadType = remoteCodec.payloadType;
                            }
                        });
                    }
                });
                localCapabilities.headerExtensions.forEach(function (hdrExt) {
                    var remoteExtensions = transceiver.remoteCapabilities &&
                        transceiver.remoteCapabilities.headerExtensions || [];
                    remoteExtensions.forEach(function (rHdrExt) {
                        if (hdrExt.uri === rHdrExt.uri) {
                            hdrExt.id = rHdrExt.id;
                        }
                    });
                });

                // generate an ssrc now, to be used later in rtpSender.send
                var sendEncodingParameters = transceiver.sendEncodingParameters || [{
                    ssrc: (2 * sdpMLineIndex + 1) * 1001
                }];
                if (track) {
                    // add RTX
                    if (edgeVersion >= 15019 && kind === 'video' &&
                        !sendEncodingParameters[0].rtx) {
                        sendEncodingParameters[0].rtx = {
                            ssrc: sendEncodingParameters[0].ssrc + 1
                        };
                    }
                }

                if (transceiver.wantReceive) {
                    transceiver.rtpReceiver = new window.RTCRtpReceiver(
                        transceiver.dtlsTransport, kind);
                }

                transceiver.localCapabilities = localCapabilities;
                transceiver.sendEncodingParameters = sendEncodingParameters;
            });

            // always offer BUNDLE and dispose on return if not supported.
            if (pc._config.bundlePolicy !== 'max-compat') {
                sdp$1 += 'a=group:BUNDLE ' + pc.transceivers.map(function (t) {
                    return t.mid;
                }).join(' ') + '\r\n';
            }
            sdp$1 += 'a=ice-options:trickle\r\n';

            pc.transceivers.forEach(function (transceiver, sdpMLineIndex) {
                sdp$1 += writeMediaSection(transceiver, transceiver.localCapabilities,
                    'offer', transceiver.stream, pc._dtlsRole);
                sdp$1 += 'a=rtcp-rsize\r\n';

                if (transceiver.iceGatherer && pc.iceGatheringState !== 'new' &&
                    (sdpMLineIndex === 0 || !pc.usingBundle)) {
                    transceiver.iceGatherer.getLocalCandidates().forEach(function (cand) {
                        cand.component = 1;
                        sdp$1 += 'a=' + sdp.writeCandidate(cand) + '\r\n';
                    });

                    if (transceiver.iceGatherer.state === 'completed') {
                        sdp$1 += 'a=end-of-candidates\r\n';
                    }
                }
            });

            var desc = new window.RTCSessionDescription({
                type: 'offer',
                sdp: sdp$1
            });
            return Promise.resolve(desc);
        };

        RTCPeerConnection.prototype.createAnswer = function () {
            var pc = this;

            if (pc._isClosed) {
                return Promise.reject(makeError('InvalidStateError',
                    'Can not call createAnswer after close'));
            }

            if (!(pc.signalingState === 'have-remote-offer' ||
                pc.signalingState === 'have-local-pranswer')) {
                return Promise.reject(makeError('InvalidStateError',
                    'Can not call createAnswer in signalingState ' + pc.signalingState));
            }

            var sdp$1 = sdp.writeSessionBoilerplate(pc._sdpSessionId,
                pc._sdpSessionVersion++);
            if (pc.usingBundle) {
                sdp$1 += 'a=group:BUNDLE ' + pc.transceivers.map(function (t) {
                    return t.mid;
                }).join(' ') + '\r\n';
            }
            sdp$1 += 'a=ice-options:trickle\r\n';

            var mediaSectionsInOffer = sdp.getMediaSections(
                pc._remoteDescription.sdp).length;
            pc.transceivers.forEach(function (transceiver, sdpMLineIndex) {
                if (sdpMLineIndex + 1 > mediaSectionsInOffer) {
                    return;
                }
                if (transceiver.rejected) {
                    if (transceiver.kind === 'application') {
                        if (transceiver.protocol === 'DTLS/SCTP') { // legacy fmt
                            sdp$1 += 'm=application 0 DTLS/SCTP 5000\r\n';
                        } else {
                            sdp$1 += 'm=application 0 ' + transceiver.protocol +
                                ' webrtc-datachannel\r\n';
                        }
                    } else if (transceiver.kind === 'audio') {
                        sdp$1 += 'm=audio 0 UDP/TLS/RTP/SAVPF 0\r\n' +
                            'a=rtpmap:0 PCMU/8000\r\n';
                    } else if (transceiver.kind === 'video') {
                        sdp$1 += 'm=video 0 UDP/TLS/RTP/SAVPF 120\r\n' +
                            'a=rtpmap:120 VP8/90000\r\n';
                    }
                    sdp$1 += 'c=IN IP4 0.0.0.0\r\n' +
                        'a=inactive\r\n' +
                        'a=mid:' + transceiver.mid + '\r\n';
                    return;
                }

                // FIXME: look at direction.
                if (transceiver.stream) {
                    var localTrack;
                    if (transceiver.kind === 'audio') {
                        localTrack = transceiver.stream.getAudioTracks()[0];
                    } else if (transceiver.kind === 'video') {
                        localTrack = transceiver.stream.getVideoTracks()[0];
                    }
                    if (localTrack) {
                        // add RTX
                        if (edgeVersion >= 15019 && transceiver.kind === 'video' &&
                            !transceiver.sendEncodingParameters[0].rtx) {
                            transceiver.sendEncodingParameters[0].rtx = {
                                ssrc: transceiver.sendEncodingParameters[0].ssrc + 1
                            };
                        }
                    }
                }

                // Calculate intersection of capabilities.
                var commonCapabilities = getCommonCapabilities(
                    transceiver.localCapabilities,
                    transceiver.remoteCapabilities);

                var hasRtx = commonCapabilities.codecs.filter(function (c) {
                    return c.name.toLowerCase() === 'rtx';
                }).length;
                if (!hasRtx && transceiver.sendEncodingParameters[0].rtx) {
                    delete transceiver.sendEncodingParameters[0].rtx;
                }

                sdp$1 += writeMediaSection(transceiver, commonCapabilities,
                    'answer', transceiver.stream, pc._dtlsRole);
                if (transceiver.rtcpParameters &&
                    transceiver.rtcpParameters.reducedSize) {
                    sdp$1 += 'a=rtcp-rsize\r\n';
                }
            });

            var desc = new window.RTCSessionDescription({
                type: 'answer',
                sdp: sdp$1
            });
            return Promise.resolve(desc);
        };

        RTCPeerConnection.prototype.addIceCandidate = function (candidate) {
            var pc = this;
            var sections;
            if (candidate && !(candidate.sdpMLineIndex !== undefined ||
                candidate.sdpMid)) {
                return Promise.reject(new TypeError('sdpMLineIndex or sdpMid required'));
            }

            // TODO: needs to go into ops queue.
            return new Promise(function (resolve, reject) {
                if (!pc._remoteDescription) {
                    return reject(makeError('InvalidStateError',
                        'Can not add ICE candidate without a remote description'));
                } else if (!candidate || candidate.candidate === '') {
                    for (var j = 0; j < pc.transceivers.length; j++) {
                        if (pc.transceivers[j].rejected) {
                            continue;
                        }
                        pc.transceivers[j].iceTransport.addRemoteCandidate({});
                        sections = sdp.getMediaSections(pc._remoteDescription.sdp);
                        sections[j] += 'a=end-of-candidates\r\n';
                        pc._remoteDescription.sdp =
                            sdp.getDescription(pc._remoteDescription.sdp) +
                            sections.join('');
                        if (pc.usingBundle) {
                            break;
                        }
                    }
                } else {
                    var sdpMLineIndex = candidate.sdpMLineIndex;
                    if (candidate.sdpMid) {
                        for (var i = 0; i < pc.transceivers.length; i++) {
                            if (pc.transceivers[i].mid === candidate.sdpMid) {
                                sdpMLineIndex = i;
                                break;
                            }
                        }
                    }
                    var transceiver = pc.transceivers[sdpMLineIndex];
                    if (transceiver) {
                        if (transceiver.rejected) {
                            return resolve();
                        }
                        var cand = Object.keys(candidate.candidate).length > 0 ?
                            sdp.parseCandidate(candidate.candidate) : {};
                        // Ignore Chrome's invalid candidates since Edge does not like them.
                        if (cand.protocol === 'tcp' && (cand.port === 0 || cand.port === 9)) {
                            return resolve();
                        }
                        // Ignore RTCP candidates, we assume RTCP-MUX.
                        if (cand.component && cand.component !== 1) {
                            return resolve();
                        }
                        // when using bundle, avoid adding candidates to the wrong
                        // ice transport. And avoid adding candidates added in the SDP.
                        if (sdpMLineIndex === 0 || (sdpMLineIndex > 0 &&
                            transceiver.iceTransport !== pc.transceivers[0].iceTransport)) {
                            if (!maybeAddCandidate(transceiver.iceTransport, cand)) {
                                return reject(makeError('OperationError',
                                    'Can not add ICE candidate'));
                            }
                        }

                        // update the remoteDescription.
                        var candidateString = candidate.candidate.trim();
                        if (candidateString.indexOf('a=') === 0) {
                            candidateString = candidateString.substr(2);
                        }
                        sections = sdp.getMediaSections(pc._remoteDescription.sdp);
                        sections[sdpMLineIndex] += 'a=' +
                            (cand.type ? candidateString : 'end-of-candidates')
                            + '\r\n';
                        pc._remoteDescription.sdp =
                            sdp.getDescription(pc._remoteDescription.sdp) +
                            sections.join('');
                    } else {
                        return reject(makeError('OperationError',
                            'Can not add ICE candidate'));
                    }
                }
                resolve();
            });
        };

        RTCPeerConnection.prototype.getStats = function (selector) {
            if (selector && selector instanceof window.MediaStreamTrack) {
                var senderOrReceiver = null;
                this.transceivers.forEach(function (transceiver) {
                    if (transceiver.rtpSender &&
                        transceiver.rtpSender.track === selector) {
                        senderOrReceiver = transceiver.rtpSender;
                    } else if (transceiver.rtpReceiver &&
                        transceiver.rtpReceiver.track === selector) {
                        senderOrReceiver = transceiver.rtpReceiver;
                    }
                });
                if (!senderOrReceiver) {
                    throw makeError('InvalidAccessError', 'Invalid selector.');
                }
                return senderOrReceiver.getStats();
            }

            var promises = [];
            this.transceivers.forEach(function (transceiver) {
                ['rtpSender', 'rtpReceiver', 'iceGatherer', 'iceTransport',
                    'dtlsTransport'].forEach(function (method) {
                    if (transceiver[method]) {
                        promises.push(transceiver[method].getStats());
                    }
                });
            });
            return Promise.all(promises).then(function (allStats) {
                var results = new Map();
                allStats.forEach(function (stats) {
                    stats.forEach(function (stat) {
                        results.set(stat.id, stat);
                    });
                });
                return results;
            });
        };

        // fix low-level stat names and return Map instead of object.
        var ortcObjects = ['RTCRtpSender', 'RTCRtpReceiver', 'RTCIceGatherer',
            'RTCIceTransport', 'RTCDtlsTransport'];
        ortcObjects.forEach(function (ortcObjectName) {
            var obj = window[ortcObjectName];
            if (obj && obj.prototype && obj.prototype.getStats) {
                var nativeGetstats = obj.prototype.getStats;
                obj.prototype.getStats = function () {
                    return nativeGetstats.apply(this)
                        .then(function (nativeStats) {
                            var mapStats = new Map();
                            Object.keys(nativeStats).forEach(function (id) {
                                nativeStats[id].type = fixStatsType(nativeStats[id]);
                                mapStats.set(id, nativeStats[id]);
                            });
                            return mapStats;
                        });
                };
            }
        });

        // legacy callback shims. Should be moved to adapter.js some days.
        var methods = ['createOffer', 'createAnswer'];
        methods.forEach(function (method) {
            var nativeMethod = RTCPeerConnection.prototype[method];
            RTCPeerConnection.prototype[method] = function () {
                var args = arguments;
                if (typeof args[0] === 'function' ||
                    typeof args[1] === 'function') { // legacy
                    return nativeMethod.apply(this, [arguments[2]])
                        .then(function (description) {
                            if (typeof args[0] === 'function') {
                                args[0].apply(null, [description]);
                            }
                        }, function (error) {
                            if (typeof args[1] === 'function') {
                                args[1].apply(null, [error]);
                            }
                        });
                }
                return nativeMethod.apply(this, arguments);
            };
        });

        methods = ['setLocalDescription', 'setRemoteDescription', 'addIceCandidate'];
        methods.forEach(function (method) {
            var nativeMethod = RTCPeerConnection.prototype[method];
            RTCPeerConnection.prototype[method] = function () {
                var args = arguments;
                if (typeof args[1] === 'function' ||
                    typeof args[2] === 'function') { // legacy
                    return nativeMethod.apply(this, arguments)
                        .then(function () {
                            if (typeof args[1] === 'function') {
                                args[1].apply(null);
                            }
                        }, function (error) {
                            if (typeof args[2] === 'function') {
                                args[2].apply(null, [error]);
                            }
                        });
                }
                return nativeMethod.apply(this, arguments);
            };
        });

        // getStats is special. It doesn't have a spec legacy method yet we support
        // getStats(something, cb) without error callbacks.
        ['getStats'].forEach(function (method) {
            var nativeMethod = RTCPeerConnection.prototype[method];
            RTCPeerConnection.prototype[method] = function () {
                var args = arguments;
                if (typeof args[1] === 'function') {
                    return nativeMethod.apply(this, arguments)
                        .then(function () {
                            if (typeof args[1] === 'function') {
                                args[1].apply(null);
                            }
                        });
                }
                return nativeMethod.apply(this, arguments);
            };
        });

        return RTCPeerConnection;
    };

    /*
	 *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
	 *
	 *  Use of this source code is governed by a BSD-style license
	 *  that can be found in the LICENSE file in the root of the source
	 *  tree.
	 */

    function shimGetUserMedia$2(window) {
        const navigator = window && window.navigator;

        const shimError_ = function (e) {
            return {
                name: {PermissionDeniedError: 'NotAllowedError'}[e.name] || e.name,
                message: e.message,
                constraint: e.constraint,
                toString() {
                    return this.name;
                }
            };
        };

        // getUserMedia error shim.
        const origGetUserMedia = navigator.mediaDevices.getUserMedia.bind(navigator.mediaDevices);
        navigator.mediaDevices.getUserMedia = function (c) {
            return origGetUserMedia(c).catch(e => Promise.reject(shimError_(e)));
        };
    }

    /*
	 *  Copyright (c) 2018 The adapter.js project authors. All Rights Reserved.
	 *
	 *  Use of this source code is governed by a BSD-style license
	 *  that can be found in the LICENSE file in the root of the source
	 *  tree.
	 */

    function shimGetDisplayMedia$1(window) {
        if (!('getDisplayMedia' in window.navigator)) {
            return;
        }
        if (!(window.navigator.mediaDevices)) {
            return;
        }
        if (window.navigator.mediaDevices &&
            'getDisplayMedia' in window.navigator.mediaDevices) {
            return;
        }
        window.navigator.mediaDevices.getDisplayMedia =
            window.navigator.getDisplayMedia.bind(window.navigator);
    }

    /*
	 *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
	 *
	 *  Use of this source code is governed by a BSD-style license
	 *  that can be found in the LICENSE file in the root of the source
	 *  tree.
	 */

    function shimPeerConnection$1(window, browserDetails) {
        if (window.RTCIceGatherer) {
            if (!window.RTCIceCandidate) {
                window.RTCIceCandidate = function RTCIceCandidate(args) {
                    return args;
                };
            }
            if (!window.RTCSessionDescription) {
                window.RTCSessionDescription = function RTCSessionDescription(args) {
                    return args;
                };
            }
            // this adds an additional event listener to MediaStrackTrack that signals
            // when a tracks enabled property was changed. Workaround for a bug in
            // addStream, see below. No longer required in 15025+
            if (browserDetails.version < 15025) {
                const origMSTEnabled = Object.getOwnPropertyDescriptor(
                    window.MediaStreamTrack.prototype, 'enabled');
                Object.defineProperty(window.MediaStreamTrack.prototype, 'enabled', {
                    set(value) {
                        origMSTEnabled.set.call(this, value);
                        const ev = new Event('enabled');
                        ev.enabled = value;
                        this.dispatchEvent(ev);
                    }
                });
            }
        }

        // ORTC defines the DTMF sender a bit different.
        // https://github.com/w3c/ortc/issues/714
        if (window.RTCRtpSender && !('dtmf' in window.RTCRtpSender.prototype)) {
            Object.defineProperty(window.RTCRtpSender.prototype, 'dtmf', {
                get() {
                    if (this._dtmf === undefined) {
                        if (this.track.kind === 'audio') {
                            this._dtmf = new window.RTCDtmfSender(this);
                        } else if (this.track.kind === 'video') {
                            this._dtmf = null;
                        }
                    }
                    return this._dtmf;
                }
            });
        }
        // Edge currently only implements the RTCDtmfSender, not the
        // RTCDTMFSender alias. See http://draft.ortc.org/#rtcdtmfsender2*
        if (window.RTCDtmfSender && !window.RTCDTMFSender) {
            window.RTCDTMFSender = window.RTCDtmfSender;
        }

        const RTCPeerConnectionShim = rtcpeerconnection(window,
            browserDetails.version);
        window.RTCPeerConnection = function RTCPeerConnection(config) {
            if (config && config.iceServers) {
                config.iceServers = filterIceServers$1(config.iceServers,
                    browserDetails.version);
                log$1('ICE servers after filtering:', config.iceServers);
            }
            return new RTCPeerConnectionShim(config);
        };
        window.RTCPeerConnection.prototype = RTCPeerConnectionShim.prototype;
    }

    function shimReplaceTrack(window) {
        // ORTC has replaceTrack -- https://github.com/w3c/ortc/issues/614
        if (window.RTCRtpSender &&
            !('replaceTrack' in window.RTCRtpSender.prototype)) {
            window.RTCRtpSender.prototype.replaceTrack =
                window.RTCRtpSender.prototype.setTrack;
        }
    }

    var edgeShim = /*#__PURE__*/Object.freeze({
        __proto__: null,
        shimPeerConnection: shimPeerConnection$1,
        shimReplaceTrack: shimReplaceTrack,
        shimGetUserMedia: shimGetUserMedia$2,
        shimGetDisplayMedia: shimGetDisplayMedia$1
    });

    /*
	 *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
	 *
	 *  Use of this source code is governed by a BSD-style license
	 *  that can be found in the LICENSE file in the root of the source
	 *  tree.
	 */

    function shimGetUserMedia$1(window, browserDetails) {
        const navigator = window && window.navigator;
        const MediaStreamTrack = window && window.MediaStreamTrack;

        navigator.getUserMedia = function (constraints, onSuccess, onError) {
            // Replace Firefox 44+'s deprecation warning with unprefixed version.
            deprecated('navigator.getUserMedia',
                'navigator.mediaDevices.getUserMedia');
            navigator.mediaDevices.getUserMedia(constraints).then(onSuccess, onError);
        };

        if (!(browserDetails.version > 55 &&
            'autoGainControl' in navigator.mediaDevices.getSupportedConstraints())) {
            const remap = function (obj, a, b) {
                if (a in obj && !(b in obj)) {
                    obj[b] = obj[a];
                    delete obj[a];
                }
            };

            const nativeGetUserMedia = navigator.mediaDevices.getUserMedia.bind(navigator.mediaDevices);
            navigator.mediaDevices.getUserMedia = function (c) {
                if (typeof c === 'object' && typeof c.audio === 'object') {
                    c = JSON.parse(JSON.stringify(c));
                    remap(c.audio, 'autoGainControl', 'mozAutoGainControl');
                    remap(c.audio, 'noiseSuppression', 'mozNoiseSuppression');
                }
                return nativeGetUserMedia(c);
            };

            if (MediaStreamTrack && MediaStreamTrack.prototype.getSettings) {
                const nativeGetSettings = MediaStreamTrack.prototype.getSettings;
                MediaStreamTrack.prototype.getSettings = function () {
                    const obj = nativeGetSettings.apply(this, arguments);
                    remap(obj, 'mozAutoGainControl', 'autoGainControl');
                    remap(obj, 'mozNoiseSuppression', 'noiseSuppression');
                    return obj;
                };
            }

            if (MediaStreamTrack && MediaStreamTrack.prototype.applyConstraints) {
                const nativeApplyConstraints =
                    MediaStreamTrack.prototype.applyConstraints;
                MediaStreamTrack.prototype.applyConstraints = function (c) {
                    if (this.kind === 'audio' && typeof c === 'object') {
                        c = JSON.parse(JSON.stringify(c));
                        remap(c, 'autoGainControl', 'mozAutoGainControl');
                        remap(c, 'noiseSuppression', 'mozNoiseSuppression');
                    }
                    return nativeApplyConstraints.apply(this, [c]);
                };
            }
        }
    }

    /*
	 *  Copyright (c) 2018 The adapter.js project authors. All Rights Reserved.
	 *
	 *  Use of this source code is governed by a BSD-style license
	 *  that can be found in the LICENSE file in the root of the source
	 *  tree.
	 */

    function shimGetDisplayMedia(window, preferredMediaSource) {
        if (window.navigator.mediaDevices &&
            'getDisplayMedia' in window.navigator.mediaDevices) {
            return;
        }
        if (!(window.navigator.mediaDevices)) {
            return;
        }
        window.navigator.mediaDevices.getDisplayMedia =
            function getDisplayMedia(constraints) {
                if (!(constraints && constraints.video)) {
                    const err = new DOMException('getDisplayMedia without video ' +
                        'constraints is undefined');
                    err.name = 'NotFoundError';
                    // from https://heycam.github.io/webidl/#idl-DOMException-error-names
                    err.code = 8;
                    return Promise.reject(err);
                }
                if (constraints.video === true) {
                    constraints.video = {mediaSource: preferredMediaSource};
                } else {
                    constraints.video.mediaSource = preferredMediaSource;
                }
                return window.navigator.mediaDevices.getUserMedia(constraints);
            };
    }

    /*
	 *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
	 *
	 *  Use of this source code is governed by a BSD-style license
	 *  that can be found in the LICENSE file in the root of the source
	 *  tree.
	 */

    function shimOnTrack(window) {
        if (typeof window === 'object' && window.RTCTrackEvent &&
            ('receiver' in window.RTCTrackEvent.prototype) &&
            !('transceiver' in window.RTCTrackEvent.prototype)) {
            Object.defineProperty(window.RTCTrackEvent.prototype, 'transceiver', {
                get() {
                    return {receiver: this.receiver};
                }
            });
        }
    }

    function shimPeerConnection(window, browserDetails) {
        if (typeof window !== 'object' ||
            !(window.RTCPeerConnection || window.mozRTCPeerConnection)) {
            return; // probably media.peerconnection.enabled=false in about:config
        }
        if (!window.RTCPeerConnection && window.mozRTCPeerConnection) {
            // very basic support for old versions.
            window.RTCPeerConnection = window.mozRTCPeerConnection;
        }

        if (browserDetails.version < 53) {
            // shim away need for obsolete RTCIceCandidate/RTCSessionDescription.
            ['setLocalDescription', 'setRemoteDescription', 'addIceCandidate']
                .forEach(function (method) {
                    const nativeMethod = window.RTCPeerConnection.prototype[method];
                    const methodObj = {
                        [method]() {
                            arguments[0] = new ((method === 'addIceCandidate') ?
                                window.RTCIceCandidate :
                                window.RTCSessionDescription)(arguments[0]);
                            return nativeMethod.apply(this, arguments);
                        }
                    };
                    window.RTCPeerConnection.prototype[method] = methodObj[method];
                });
        }

        const modernStatsTypes = {
            inboundrtp: 'inbound-rtp',
            outboundrtp: 'outbound-rtp',
            candidatepair: 'candidate-pair',
            localcandidate: 'local-candidate',
            remotecandidate: 'remote-candidate'
        };

        const nativeGetStats = window.RTCPeerConnection.prototype.getStats;
        window.RTCPeerConnection.prototype.getStats = function getStats() {
            const [selector, onSucc, onErr] = arguments;
            return nativeGetStats.apply(this, [selector || null])
                .then(stats => {
                    if (browserDetails.version < 53 && !onSucc) {
                        // Shim only promise getStats with spec-hyphens in type names
                        // Leave callback version alone; misc old uses of forEach before Map
                        try {
                            stats.forEach(stat => {
                                stat.type = modernStatsTypes[stat.type] || stat.type;
                            });
                        } catch (e) {
                            if (e.name !== 'TypeError') {
                                throw e;
                            }
                            // Avoid TypeError: "type" is read-only, in old versions. 34-43ish
                            stats.forEach((stat, i) => {
                                stats.set(i, Object.assign({}, stat, {
                                    type: modernStatsTypes[stat.type] || stat.type
                                }));
                            });
                        }
                    }
                    return stats;
                })
                .then(onSucc, onErr);
        };
    }

    function shimSenderGetStats(window) {
        if (!(typeof window === 'object' && window.RTCPeerConnection &&
            window.RTCRtpSender)) {
            return;
        }
        if (window.RTCRtpSender && 'getStats' in window.RTCRtpSender.prototype) {
            return;
        }
        const origGetSenders = window.RTCPeerConnection.prototype.getSenders;
        if (origGetSenders) {
            window.RTCPeerConnection.prototype.getSenders = function getSenders() {
                const senders = origGetSenders.apply(this, []);
                senders.forEach(sender => sender._pc = this);
                return senders;
            };
        }

        const origAddTrack = window.RTCPeerConnection.prototype.addTrack;
        if (origAddTrack) {
            window.RTCPeerConnection.prototype.addTrack = function addTrack() {
                const sender = origAddTrack.apply(this, arguments);
                sender._pc = this;
                return sender;
            };
        }
        window.RTCRtpSender.prototype.getStats = function getStats() {
            return this.track ? this._pc.getStats(this.track) :
                Promise.resolve(new Map());
        };
    }

    function shimReceiverGetStats(window) {
        if (!(typeof window === 'object' && window.RTCPeerConnection &&
            window.RTCRtpSender)) {
            return;
        }
        if (window.RTCRtpSender && 'getStats' in window.RTCRtpReceiver.prototype) {
            return;
        }
        const origGetReceivers = window.RTCPeerConnection.prototype.getReceivers;
        if (origGetReceivers) {
            window.RTCPeerConnection.prototype.getReceivers = function getReceivers() {
                const receivers = origGetReceivers.apply(this, []);
                receivers.forEach(receiver => receiver._pc = this);
                return receivers;
            };
        }
        wrapPeerConnectionEvent(window, 'track', e => {
            e.receiver._pc = e.srcElement;
            return e;
        });
        window.RTCRtpReceiver.prototype.getStats = function getStats() {
            return this._pc.getStats(this.track);
        };
    }

    function shimRemoveStream(window) {
        if (!window.RTCPeerConnection ||
            'removeStream' in window.RTCPeerConnection.prototype) {
            return;
        }
        window.RTCPeerConnection.prototype.removeStream =
            function removeStream(stream) {
                deprecated('removeStream', 'removeTrack');
                this.getSenders().forEach(sender => {
                    if (sender.track && stream.getTracks().includes(sender.track)) {
                        this.removeTrack(sender);
                    }
                });
            };
    }

    function shimRTCDataChannel(window) {
        // rename DataChannel to RTCDataChannel (native fix in FF60):
        // https://bugzilla.mozilla.org/show_bug.cgi?id=1173851
        if (window.DataChannel && !window.RTCDataChannel) {
            window.RTCDataChannel = window.DataChannel;
        }
    }

    function shimAddTransceiver(window) {
        // https://github.com/webrtcHacks/adapter/issues/998#issuecomment-516921647
        // Firefox ignores the init sendEncodings options passed to addTransceiver
        // https://bugzilla.mozilla.org/show_bug.cgi?id=1396918
        if (!(typeof window === 'object' && window.RTCPeerConnection)) {
            return;
        }
        const origAddTransceiver = window.RTCPeerConnection.prototype.addTransceiver;
        if (origAddTransceiver) {
            window.RTCPeerConnection.prototype.addTransceiver =
                function addTransceiver() {
                    this.setParametersPromises = [];
                    const initParameters = arguments[1];
                    const shouldPerformCheck = initParameters &&
                        'sendEncodings' in initParameters;
                    if (shouldPerformCheck) {
                        // If sendEncodings params are provided, validate grammar
                        initParameters.sendEncodings.forEach((encodingParam) => {
                            if ('rid' in encodingParam) {
                                const ridRegex = /^[a-z0-9]{0,16}$/i;
                                if (!ridRegex.test(encodingParam.rid)) {
                                    throw new TypeError('Invalid RID value provided.');
                                }
                            }
                            if ('scaleResolutionDownBy' in encodingParam) {
                                if (!(parseFloat(encodingParam.scaleResolutionDownBy) >= 1.0)) {
                                    throw new RangeError('scale_resolution_down_by must be >= 1.0');
                                }
                            }
                            if ('maxFramerate' in encodingParam) {
                                if (!(parseFloat(encodingParam.maxFramerate) >= 0)) {
                                    throw new RangeError('max_framerate must be >= 0.0');
                                }
                            }
                        });
                    }
                    const transceiver = origAddTransceiver.apply(this, arguments);
                    if (shouldPerformCheck) {
                        // Check if the init options were applied. If not we do this in an
                        // asynchronous way and save the promise reference in a global object.
                        // This is an ugly hack, but at the same time is way more robust than
                        // checking the sender parameters before and after the createOffer
                        // Also note that after the createoffer we are not 100% sure that
                        // the params were asynchronously applied so we might miss the
                        // opportunity to recreate offer.
                        const {sender} = transceiver;
                        const params = sender.getParameters();
                        if (!('encodings' in params) ||
                            // Avoid being fooled by patched getParameters() below.
                            (params.encodings.length === 1 &&
                                Object.keys(params.encodings[0]).length === 0)) {
                            params.encodings = initParameters.sendEncodings;
                            sender.sendEncodings = initParameters.sendEncodings;
                            this.setParametersPromises.push(sender.setParameters(params)
                                .then(() => {
                                    delete sender.sendEncodings;
                                }).catch(() => {
                                    delete sender.sendEncodings;
                                })
                            );
                        }
                    }
                    return transceiver;
                };
        }
    }

    function shimGetParameters(window) {
        if (!(typeof window === 'object' && window.RTCRtpSender)) {
            return;
        }
        const origGetParameters = window.RTCRtpSender.prototype.getParameters;
        if (origGetParameters) {
            window.RTCRtpSender.prototype.getParameters =
                function getParameters() {
                    const params = origGetParameters.apply(this, arguments);
                    if (!('encodings' in params)) {
                        params.encodings = [].concat(this.sendEncodings || [{}]);
                    }
                    return params;
                };
        }
    }

    function shimCreateOffer(window) {
        // https://github.com/webrtcHacks/adapter/issues/998#issuecomment-516921647
        // Firefox ignores the init sendEncodings options passed to addTransceiver
        // https://bugzilla.mozilla.org/show_bug.cgi?id=1396918
        if (!(typeof window === 'object' && window.RTCPeerConnection)) {
            return;
        }
        const origCreateOffer = window.RTCPeerConnection.prototype.createOffer;
        window.RTCPeerConnection.prototype.createOffer = function createOffer() {
            if (this.setParametersPromises && this.setParametersPromises.length) {
                return Promise.all(this.setParametersPromises)
                    .then(() => {
                        return origCreateOffer.apply(this, arguments);
                    })
                    .finally(() => {
                        this.setParametersPromises = [];
                    });
            }
            return origCreateOffer.apply(this, arguments);
        };
    }

    function shimCreateAnswer(window) {
        // https://github.com/webrtcHacks/adapter/issues/998#issuecomment-516921647
        // Firefox ignores the init sendEncodings options passed to addTransceiver
        // https://bugzilla.mozilla.org/show_bug.cgi?id=1396918
        if (!(typeof window === 'object' && window.RTCPeerConnection)) {
            return;
        }
        const origCreateAnswer = window.RTCPeerConnection.prototype.createAnswer;
        window.RTCPeerConnection.prototype.createAnswer = function createAnswer() {
            if (this.setParametersPromises && this.setParametersPromises.length) {
                return Promise.all(this.setParametersPromises)
                    .then(() => {
                        return origCreateAnswer.apply(this, arguments);
                    })
                    .finally(() => {
                        this.setParametersPromises = [];
                    });
            }
            return origCreateAnswer.apply(this, arguments);
        };
    }

    var firefoxShim = /*#__PURE__*/Object.freeze({
        __proto__: null,
        shimOnTrack: shimOnTrack,
        shimPeerConnection: shimPeerConnection,
        shimSenderGetStats: shimSenderGetStats,
        shimReceiverGetStats: shimReceiverGetStats,
        shimRemoveStream: shimRemoveStream,
        shimRTCDataChannel: shimRTCDataChannel,
        shimAddTransceiver: shimAddTransceiver,
        shimGetParameters: shimGetParameters,
        shimCreateOffer: shimCreateOffer,
        shimCreateAnswer: shimCreateAnswer,
        shimGetUserMedia: shimGetUserMedia$1,
        shimGetDisplayMedia: shimGetDisplayMedia
    });

    /*
	 *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
	 *
	 *  Use of this source code is governed by a BSD-style license
	 *  that can be found in the LICENSE file in the root of the source
	 *  tree.
	 */

    function shimLocalStreamsAPI(window) {
        if (typeof window !== 'object' || !window.RTCPeerConnection) {
            return;
        }
        if (!('getLocalStreams' in window.RTCPeerConnection.prototype)) {
            window.RTCPeerConnection.prototype.getLocalStreams =
                function getLocalStreams() {
                    if (!this._localStreams) {
                        this._localStreams = [];
                    }
                    return this._localStreams;
                };
        }
        if (!('addStream' in window.RTCPeerConnection.prototype)) {
            const _addTrack = window.RTCPeerConnection.prototype.addTrack;
            window.RTCPeerConnection.prototype.addStream = function addStream(stream) {
                if (!this._localStreams) {
                    this._localStreams = [];
                }
                if (!this._localStreams.includes(stream)) {
                    this._localStreams.push(stream);
                }
                // Try to emulate Chrome's behaviour of adding in audio-video order.
                // Safari orders by track id.
                stream.getAudioTracks().forEach(track => _addTrack.call(this, track,
                    stream));
                stream.getVideoTracks().forEach(track => _addTrack.call(this, track,
                    stream));
            };

            window.RTCPeerConnection.prototype.addTrack =
                function addTrack(track, ...streams) {
                    if (streams) {
                        streams.forEach((stream) => {
                            if (!this._localStreams) {
                                this._localStreams = [stream];
                            } else if (!this._localStreams.includes(stream)) {
                                this._localStreams.push(stream);
                            }
                        });
                    }
                    return _addTrack.apply(this, arguments);
                };
        }
        if (!('removeStream' in window.RTCPeerConnection.prototype)) {
            window.RTCPeerConnection.prototype.removeStream =
                function removeStream(stream) {
                    if (!this._localStreams) {
                        this._localStreams = [];
                    }
                    const index = this._localStreams.indexOf(stream);
                    if (index === -1) {
                        return;
                    }
                    this._localStreams.splice(index, 1);
                    const tracks = stream.getTracks();
                    this.getSenders().forEach(sender => {
                        if (tracks.includes(sender.track)) {
                            this.removeTrack(sender);
                        }
                    });
                };
        }
    }

    function shimRemoteStreamsAPI(window) {
        if (typeof window !== 'object' || !window.RTCPeerConnection) {
            return;
        }
        if (!('getRemoteStreams' in window.RTCPeerConnection.prototype)) {
            window.RTCPeerConnection.prototype.getRemoteStreams =
                function getRemoteStreams() {
                    return this._remoteStreams ? this._remoteStreams : [];
                };
        }
        if (!('onaddstream' in window.RTCPeerConnection.prototype)) {
            Object.defineProperty(window.RTCPeerConnection.prototype, 'onaddstream', {
                get() {
                    return this._onaddstream;
                },
                set(f) {
                    if (this._onaddstream) {
                        this.removeEventListener('addstream', this._onaddstream);
                        this.removeEventListener('track', this._onaddstreampoly);
                    }
                    this.addEventListener('addstream', this._onaddstream = f);
                    this.addEventListener('track', this._onaddstreampoly = (e) => {
                        e.streams.forEach(stream => {
                            if (!this._remoteStreams) {
                                this._remoteStreams = [];
                            }
                            if (this._remoteStreams.includes(stream)) {
                                return;
                            }
                            this._remoteStreams.push(stream);
                            const event = new Event('addstream');
                            event.stream = stream;
                            this.dispatchEvent(event);
                        });
                    });
                }
            });
            const origSetRemoteDescription =
                window.RTCPeerConnection.prototype.setRemoteDescription;
            window.RTCPeerConnection.prototype.setRemoteDescription =
                function setRemoteDescription() {
                    const pc = this;
                    if (!this._onaddstreampoly) {
                        this.addEventListener('track', this._onaddstreampoly = function (e) {
                            e.streams.forEach(stream => {
                                if (!pc._remoteStreams) {
                                    pc._remoteStreams = [];
                                }
                                if (pc._remoteStreams.indexOf(stream) >= 0) {
                                    return;
                                }
                                pc._remoteStreams.push(stream);
                                const event = new Event('addstream');
                                event.stream = stream;
                                pc.dispatchEvent(event);
                            });
                        });
                    }
                    return origSetRemoteDescription.apply(pc, arguments);
                };
        }
    }

    function shimCallbacksAPI(window) {
        if (typeof window !== 'object' || !window.RTCPeerConnection) {
            return;
        }
        const prototype = window.RTCPeerConnection.prototype;
        const origCreateOffer = prototype.createOffer;
        const origCreateAnswer = prototype.createAnswer;
        const setLocalDescription = prototype.setLocalDescription;
        const setRemoteDescription = prototype.setRemoteDescription;
        const addIceCandidate = prototype.addIceCandidate;

        prototype.createOffer =
            function createOffer(successCallback, failureCallback) {
                const options = (arguments.length >= 2) ? arguments[2] : arguments[0];
                const promise = origCreateOffer.apply(this, [options]);
                if (!failureCallback) {
                    return promise;
                }
                promise.then(successCallback, failureCallback);
                return Promise.resolve();
            };

        prototype.createAnswer =
            function createAnswer(successCallback, failureCallback) {
                const options = (arguments.length >= 2) ? arguments[2] : arguments[0];
                const promise = origCreateAnswer.apply(this, [options]);
                if (!failureCallback) {
                    return promise;
                }
                promise.then(successCallback, failureCallback);
                return Promise.resolve();
            };

        let withCallback = function (description, successCallback, failureCallback) {
            const promise = setLocalDescription.apply(this, [description]);
            if (!failureCallback) {
                return promise;
            }
            promise.then(successCallback, failureCallback);
            return Promise.resolve();
        };
        prototype.setLocalDescription = withCallback;

        withCallback = function (description, successCallback, failureCallback) {
            const promise = setRemoteDescription.apply(this, [description]);
            if (!failureCallback) {
                return promise;
            }
            promise.then(successCallback, failureCallback);
            return Promise.resolve();
        };
        prototype.setRemoteDescription = withCallback;

        withCallback = function (candidate, successCallback, failureCallback) {
            const promise = addIceCandidate.apply(this, [candidate]);
            if (!failureCallback) {
                return promise;
            }
            promise.then(successCallback, failureCallback);
            return Promise.resolve();
        };
        prototype.addIceCandidate = withCallback;
    }

    function shimGetUserMedia(window) {
        const navigator = window && window.navigator;

        if (navigator.mediaDevices && navigator.mediaDevices.getUserMedia) {
            // shim not needed in Safari 12.1
            const mediaDevices = navigator.mediaDevices;
            const _getUserMedia = mediaDevices.getUserMedia.bind(mediaDevices);
            navigator.mediaDevices.getUserMedia = (constraints) => {
                return _getUserMedia(shimConstraints(constraints));
            };
        }

        if (!navigator.getUserMedia && navigator.mediaDevices &&
            navigator.mediaDevices.getUserMedia) {
            navigator.getUserMedia = function getUserMedia(constraints, cb, errcb) {
                navigator.mediaDevices.getUserMedia(constraints)
                    .then(cb, errcb);
            }.bind(navigator);
        }
    }

    function shimConstraints(constraints) {
        if (constraints && constraints.video !== undefined) {
            return Object.assign({},
                constraints,
                {video: compactObject(constraints.video)}
            );
        }

        return constraints;
    }

    function shimRTCIceServerUrls(window) {
        if (!window.RTCPeerConnection) {
            return;
        }
        // migrate from non-spec RTCIceServer.url to RTCIceServer.urls
        const OrigPeerConnection = window.RTCPeerConnection;
        window.RTCPeerConnection =
            function RTCPeerConnection(pcConfig, pcConstraints) {
                if (pcConfig && pcConfig.iceServers) {
                    const newIceServers = [];
                    for (let i = 0; i < pcConfig.iceServers.length; i++) {
                        let server = pcConfig.iceServers[i];
                        if (!server.hasOwnProperty('urls') &&
                            server.hasOwnProperty('url')) {
                            deprecated('RTCIceServer.url', 'RTCIceServer.urls');
                            server = JSON.parse(JSON.stringify(server));
                            server.urls = server.url;
                            delete server.url;
                            newIceServers.push(server);
                        } else {
                            newIceServers.push(pcConfig.iceServers[i]);
                        }
                    }
                    pcConfig.iceServers = newIceServers;
                }
                return new OrigPeerConnection(pcConfig, pcConstraints);
            };
        window.RTCPeerConnection.prototype = OrigPeerConnection.prototype;
        // wrap static methods. Currently just generateCertificate.
        if ('generateCertificate' in OrigPeerConnection) {
            Object.defineProperty(window.RTCPeerConnection, 'generateCertificate', {
                get() {
                    return OrigPeerConnection.generateCertificate;
                }
            });
        }
    }

    function shimTrackEventTransceiver(window) {
        // Add event.transceiver member over deprecated event.receiver
        if (typeof window === 'object' && window.RTCTrackEvent &&
            'receiver' in window.RTCTrackEvent.prototype &&
            !('transceiver' in window.RTCTrackEvent.prototype)) {
            Object.defineProperty(window.RTCTrackEvent.prototype, 'transceiver', {
                get() {
                    return {receiver: this.receiver};
                }
            });
        }
    }

    function shimCreateOfferLegacy(window) {
        const origCreateOffer = window.RTCPeerConnection.prototype.createOffer;
        window.RTCPeerConnection.prototype.createOffer =
            function createOffer(offerOptions) {
                if (offerOptions) {
                    if (typeof offerOptions.offerToReceiveAudio !== 'undefined') {
                        // support bit values
                        offerOptions.offerToReceiveAudio =
                            !!offerOptions.offerToReceiveAudio;
                    }
                    const audioTransceiver = this.getTransceivers().find(transceiver =>
                        transceiver.receiver.track.kind === 'audio');
                    if (offerOptions.offerToReceiveAudio === false && audioTransceiver) {
                        if (audioTransceiver.direction === 'sendrecv') {
                            if (audioTransceiver.setDirection) {
                                audioTransceiver.setDirection('sendonly');
                            } else {
                                audioTransceiver.direction = 'sendonly';
                            }
                        } else if (audioTransceiver.direction === 'recvonly') {
                            if (audioTransceiver.setDirection) {
                                audioTransceiver.setDirection('inactive');
                            } else {
                                audioTransceiver.direction = 'inactive';
                            }
                        }
                    } else if (offerOptions.offerToReceiveAudio === true &&
                        !audioTransceiver) {
                        this.addTransceiver('audio');
                    }

                    if (typeof offerOptions.offerToReceiveVideo !== 'undefined') {
                        // support bit values
                        offerOptions.offerToReceiveVideo =
                            !!offerOptions.offerToReceiveVideo;
                    }
                    const videoTransceiver = this.getTransceivers().find(transceiver =>
                        transceiver.receiver.track.kind === 'video');
                    if (offerOptions.offerToReceiveVideo === false && videoTransceiver) {
                        if (videoTransceiver.direction === 'sendrecv') {
                            if (videoTransceiver.setDirection) {
                                videoTransceiver.setDirection('sendonly');
                            } else {
                                videoTransceiver.direction = 'sendonly';
                            }
                        } else if (videoTransceiver.direction === 'recvonly') {
                            if (videoTransceiver.setDirection) {
                                videoTransceiver.setDirection('inactive');
                            } else {
                                videoTransceiver.direction = 'inactive';
                            }
                        }
                    } else if (offerOptions.offerToReceiveVideo === true &&
                        !videoTransceiver) {
                        this.addTransceiver('video');
                    }
                }
                return origCreateOffer.apply(this, arguments);
            };
    }

    function shimAudioContext(window) {
        if (typeof window !== 'object' || window.AudioContext) {
            return;
        }
        window.AudioContext = window.webkitAudioContext;
    }

    var safariShim = /*#__PURE__*/Object.freeze({
        __proto__: null,
        shimLocalStreamsAPI: shimLocalStreamsAPI,
        shimRemoteStreamsAPI: shimRemoteStreamsAPI,
        shimCallbacksAPI: shimCallbacksAPI,
        shimGetUserMedia: shimGetUserMedia,
        shimConstraints: shimConstraints,
        shimRTCIceServerUrls: shimRTCIceServerUrls,
        shimTrackEventTransceiver: shimTrackEventTransceiver,
        shimCreateOfferLegacy: shimCreateOfferLegacy,
        shimAudioContext: shimAudioContext
    });

    /*
	 *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
	 *
	 *  Use of this source code is governed by a BSD-style license
	 *  that can be found in the LICENSE file in the root of the source
	 *  tree.
	 */

    function shimRTCIceCandidate(window) {
        // foundation is arbitrarily chosen as an indicator for full support for
        // https://w3c.github.io/webrtc-pc/#rtcicecandidate-interface
        if (!window.RTCIceCandidate || (window.RTCIceCandidate && 'foundation' in
            window.RTCIceCandidate.prototype)) {
            return;
        }

        const NativeRTCIceCandidate = window.RTCIceCandidate;
        window.RTCIceCandidate = function RTCIceCandidate(args) {
            // Remove the a= which shouldn't be part of the candidate string.
            if (typeof args === 'object' && args.candidate &&
                args.candidate.indexOf('a=') === 0) {
                args = JSON.parse(JSON.stringify(args));
                args.candidate = args.candidate.substr(2);
            }

            if (args.candidate && args.candidate.length) {
                // Augment the native candidate with the parsed fields.
                const nativeCandidate = new NativeRTCIceCandidate(args);
                const parsedCandidate = sdp.parseCandidate(args.candidate);
                const augmentedCandidate = Object.assign(nativeCandidate,
                    parsedCandidate);

                // Add a serializer that does not serialize the extra attributes.
                augmentedCandidate.toJSON = function toJSON() {
                    return {
                        candidate: augmentedCandidate.candidate,
                        sdpMid: augmentedCandidate.sdpMid,
                        sdpMLineIndex: augmentedCandidate.sdpMLineIndex,
                        usernameFragment: augmentedCandidate.usernameFragment,
                    };
                };
                return augmentedCandidate;
            }
            return new NativeRTCIceCandidate(args);
        };
        window.RTCIceCandidate.prototype = NativeRTCIceCandidate.prototype;

        // Hook up the augmented candidate in onicecandidate and
        // addEventListener('icecandidate', ...)
        wrapPeerConnectionEvent(window, 'icecandidate', e => {
            if (e.candidate) {
                Object.defineProperty(e, 'candidate', {
                    value: new window.RTCIceCandidate(e.candidate),
                    writable: 'false'
                });
            }
            return e;
        });
    }

    function shimMaxMessageSize(window, browserDetails) {
        if (!window.RTCPeerConnection) {
            return;
        }

        if (!('sctp' in window.RTCPeerConnection.prototype)) {
            Object.defineProperty(window.RTCPeerConnection.prototype, 'sctp', {
                get() {
                    return typeof this._sctp === 'undefined' ? null : this._sctp;
                }
            });
        }

        const sctpInDescription = function (description) {
            if (!description || !description.sdp) {
                return false;
            }
            const sections = sdp.splitSections(description.sdp);
            sections.shift();
            return sections.some(mediaSection => {
                const mLine = sdp.parseMLine(mediaSection);
                return mLine && mLine.kind === 'application'
                    && mLine.protocol.indexOf('SCTP') !== -1;
            });
        };

        const getRemoteFirefoxVersion = function (description) {
            // TODO: Is there a better solution for detecting Firefox?
            const match = description.sdp.match(/mozilla...THIS_IS_SDPARTA-(\d+)/);
            if (match === null || match.length < 2) {
                return -1;
            }
            const version = parseInt(match[1], 10);
            // Test for NaN (yes, this is ugly)
            return version !== version ? -1 : version;
        };

        const getCanSendMaxMessageSize = function (remoteIsFirefox) {
            // Every implementation we know can send at least 64 KiB.
            // Note: Although Chrome is technically able to send up to 256 KiB, the
            //       data does not reach the other peer reliably.
            //       See: https://bugs.chromium.org/p/webrtc/issues/detail?id=8419
            let canSendMaxMessageSize = 65536;
            if (browserDetails.browser === 'firefox') {
                if (browserDetails.version < 57) {
                    if (remoteIsFirefox === -1) {
                        // FF < 57 will send in 16 KiB chunks using the deprecated PPID
                        // fragmentation.
                        canSendMaxMessageSize = 16384;
                    } else {
                        // However, other FF (and RAWRTC) can reassemble PPID-fragmented
                        // messages. Thus, supporting ~2 GiB when sending.
                        canSendMaxMessageSize = 2147483637;
                    }
                } else if (browserDetails.version < 60) {
                    // Currently, all FF >= 57 will reset the remote maximum message size
                    // to the default value when a data channel is created at a later
                    // stage. :(
                    // See: https://bugzilla.mozilla.org/show_bug.cgi?id=1426831
                    canSendMaxMessageSize =
                        browserDetails.version === 57 ? 65535 : 65536;
                } else {
                    // FF >= 60 supports sending ~2 GiB
                    canSendMaxMessageSize = 2147483637;
                }
            }
            return canSendMaxMessageSize;
        };

        const getMaxMessageSize = function (description, remoteIsFirefox) {
            // Note: 65536 bytes is the default value from the SDP spec. Also,
            //       every implementation we know supports receiving 65536 bytes.
            let maxMessageSize = 65536;

            // FF 57 has a slightly incorrect default remote max message size, so
            // we need to adjust it here to avoid a failure when sending.
            // See: https://bugzilla.mozilla.org/show_bug.cgi?id=1425697
            if (browserDetails.browser === 'firefox'
                && browserDetails.version === 57) {
                maxMessageSize = 65535;
            }

            const match = sdp.matchPrefix(description.sdp,
                'a=max-message-size:');
            if (match.length > 0) {
                maxMessageSize = parseInt(match[0].substr(19), 10);
            } else if (browserDetails.browser === 'firefox' &&
                remoteIsFirefox !== -1) {
                // If the maximum message size is not present in the remote SDP and
                // both local and remote are Firefox, the remote peer can receive
                // ~2 GiB.
                maxMessageSize = 2147483637;
            }
            return maxMessageSize;
        };

        const origSetRemoteDescription =
            window.RTCPeerConnection.prototype.setRemoteDescription;
        window.RTCPeerConnection.prototype.setRemoteDescription =
            function setRemoteDescription() {
                this._sctp = null;
                // Chrome decided to not expose .sctp in plan-b mode.
                // As usual, adapter.js has to do an 'ugly worakaround'
                // to cover up the mess.
                if (browserDetails.browser === 'chrome' && browserDetails.version >= 76) {
                    const {sdpSemantics} = this.getConfiguration();
                    if (sdpSemantics === 'plan-b') {
                        Object.defineProperty(this, 'sctp', {
                            get() {
                                return typeof this._sctp === 'undefined' ? null : this._sctp;
                            },
                            enumerable: true,
                            configurable: true,
                        });
                    }
                }

                if (sctpInDescription(arguments[0])) {
                    // Check if the remote is FF.
                    const isFirefox = getRemoteFirefoxVersion(arguments[0]);

                    // Get the maximum message size the local peer is capable of sending
                    const canSendMMS = getCanSendMaxMessageSize(isFirefox);

                    // Get the maximum message size of the remote peer.
                    const remoteMMS = getMaxMessageSize(arguments[0], isFirefox);

                    // Determine final maximum message size
                    let maxMessageSize;
                    if (canSendMMS === 0 && remoteMMS === 0) {
                        maxMessageSize = Number.POSITIVE_INFINITY;
                    } else if (canSendMMS === 0 || remoteMMS === 0) {
                        maxMessageSize = Math.max(canSendMMS, remoteMMS);
                    } else {
                        maxMessageSize = Math.min(canSendMMS, remoteMMS);
                    }

                    // Create a dummy RTCSctpTransport object and the 'maxMessageSize'
                    // attribute.
                    const sctp = {};
                    Object.defineProperty(sctp, 'maxMessageSize', {
                        get() {
                            return maxMessageSize;
                        }
                    });
                    this._sctp = sctp;
                }

                return origSetRemoteDescription.apply(this, arguments);
            };
    }

    function shimSendThrowTypeError(window) {
        if (!(window.RTCPeerConnection &&
            'createDataChannel' in window.RTCPeerConnection.prototype)) {
            return;
        }

        // Note: Although Firefox >= 57 has a native implementation, the maximum
        //       message size can be reset for all data channels at a later stage.
        //       See: https://bugzilla.mozilla.org/show_bug.cgi?id=1426831

        function wrapDcSend(dc, pc) {
            const origDataChannelSend = dc.send;
            dc.send = function send() {
                const data = arguments[0];
                const length = data.length || data.size || data.byteLength;
                if (dc.readyState === 'open' &&
                    pc.sctp && length > pc.sctp.maxMessageSize) {
                    throw new TypeError('Message too large (can send a maximum of ' +
                        pc.sctp.maxMessageSize + ' bytes)');
                }
                return origDataChannelSend.apply(dc, arguments);
            };
        }

        const origCreateDataChannel =
            window.RTCPeerConnection.prototype.createDataChannel;
        window.RTCPeerConnection.prototype.createDataChannel =
            function createDataChannel() {
                const dataChannel = origCreateDataChannel.apply(this, arguments);
                wrapDcSend(dataChannel, this);
                return dataChannel;
            };
        wrapPeerConnectionEvent(window, 'datachannel', e => {
            wrapDcSend(e.channel, e.target);
            return e;
        });
    }


    /* shims RTCConnectionState by pretending it is the same as iceConnectionState.
	 * See https://bugs.chromium.org/p/webrtc/issues/detail?id=6145#c12
	 * for why this is a valid hack in Chrome. In Firefox it is slightly incorrect
	 * since DTLS failures would be hidden. See
	 * https://bugzilla.mozilla.org/show_bug.cgi?id=1265827
	 * for the Firefox tracking bug.
	 */
    function shimConnectionState(window) {
        if (!window.RTCPeerConnection ||
            'connectionState' in window.RTCPeerConnection.prototype) {
            return;
        }
        const proto = window.RTCPeerConnection.prototype;
        Object.defineProperty(proto, 'connectionState', {
            get() {
                return {
                    completed: 'connected',
                    checking: 'connecting'
                }[this.iceConnectionState] || this.iceConnectionState;
            },
            enumerable: true,
            configurable: true
        });
        Object.defineProperty(proto, 'onconnectionstatechange', {
            get() {
                return this._onconnectionstatechange || null;
            },
            set(cb) {
                if (this._onconnectionstatechange) {
                    this.removeEventListener('connectionstatechange',
                        this._onconnectionstatechange);
                    delete this._onconnectionstatechange;
                }
                if (cb) {
                    this.addEventListener('connectionstatechange',
                        this._onconnectionstatechange = cb);
                }
            },
            enumerable: true,
            configurable: true
        });

        ['setLocalDescription', 'setRemoteDescription'].forEach((method) => {
            const origMethod = proto[method];
            proto[method] = function () {
                if (!this._connectionstatechangepoly) {
                    this._connectionstatechangepoly = e => {
                        const pc = e.target;
                        if (pc._lastConnectionState !== pc.connectionState) {
                            pc._lastConnectionState = pc.connectionState;
                            const newEvent = new Event('connectionstatechange', e);
                            pc.dispatchEvent(newEvent);
                        }
                        return e;
                    };
                    this.addEventListener('iceconnectionstatechange',
                        this._connectionstatechangepoly);
                }
                return origMethod.apply(this, arguments);
            };
        });
    }

    function removeExtmapAllowMixed(window, browserDetails) {
        /* remove a=extmap-allow-mixed for webrtc.org < M71 */
        if (!window.RTCPeerConnection) {
            return;
        }
        if (browserDetails.browser === 'chrome' && browserDetails.version >= 71) {
            return;
        }
        if (browserDetails.browser === 'safari' && browserDetails.version >= 605) {
            return;
        }
        const nativeSRD = window.RTCPeerConnection.prototype.setRemoteDescription;
        window.RTCPeerConnection.prototype.setRemoteDescription =
            function setRemoteDescription(desc) {
                if (desc && desc.sdp && desc.sdp.indexOf('\na=extmap-allow-mixed') !== -1) {
                    const sdp = desc.sdp.split('\n').filter((line) => {
                        return line.trim() !== 'a=extmap-allow-mixed';
                    }).join('\n');
                    // Safari enforces read-only-ness of RTCSessionDescription fields.
                    if (window.RTCSessionDescription &&
                        desc instanceof window.RTCSessionDescription) {
                        arguments[0] = new window.RTCSessionDescription({
                            type: desc.type,
                            sdp,
                        });
                    } else {
                        desc.sdp = sdp;
                    }
                }
                return nativeSRD.apply(this, arguments);
            };
    }

    function shimAddIceCandidateNullOrEmpty(window, browserDetails) {
        // Support for addIceCandidate(null or undefined)
        // as well as addIceCandidate({candidate: "", ...})
        // https://bugs.chromium.org/p/chromium/issues/detail?id=978582
        // Note: must be called before other polyfills which change the signature.
        if (!(window.RTCPeerConnection && window.RTCPeerConnection.prototype)) {
            return;
        }
        const nativeAddIceCandidate =
            window.RTCPeerConnection.prototype.addIceCandidate;
        if (!nativeAddIceCandidate || nativeAddIceCandidate.length === 0) {
            return;
        }
        window.RTCPeerConnection.prototype.addIceCandidate =
            function addIceCandidate() {
                if (!arguments[0]) {
                    if (arguments[1]) {
                        arguments[1].apply(null);
                    }
                    return Promise.resolve();
                }
                // Firefox 68+ emits and processes {candidate: "", ...}, ignore
                // in older versions.
                // Native support for ignoring exists for Chrome M77+.
                // Safari ignores as well, exact version unknown but works in the same
                // version that also ignores addIceCandidate(null).
                if (((browserDetails.browser === 'chrome' && browserDetails.version < 78)
                        || (browserDetails.browser === 'firefox'
                            && browserDetails.version < 68)
                        || (browserDetails.browser === 'safari'))
                    && arguments[0] && arguments[0].candidate === '') {
                    return Promise.resolve();
                }
                return nativeAddIceCandidate.apply(this, arguments);
            };
    }

    var commonShim = /*#__PURE__*/Object.freeze({
        __proto__: null,
        shimRTCIceCandidate: shimRTCIceCandidate,
        shimMaxMessageSize: shimMaxMessageSize,
        shimSendThrowTypeError: shimSendThrowTypeError,
        shimConnectionState: shimConnectionState,
        removeExtmapAllowMixed: removeExtmapAllowMixed,
        shimAddIceCandidateNullOrEmpty: shimAddIceCandidateNullOrEmpty
    });

    /*
	 *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
	 *
	 *  Use of this source code is governed by a BSD-style license
	 *  that can be found in the LICENSE file in the root of the source
	 *  tree.
	 */

    // Shimming starts here.
    function adapterFactory({window} = {}, options = {
        shimChrome: true,
        shimFirefox: true,
        shimEdge: true,
        shimSafari: true,
    }) {
        // Utils.
        const logging = log$1;
        const browserDetails = detectBrowser(window);

        const adapter = {
            browserDetails,
            commonShim,
            extractVersion: extractVersion,
            disableLog: disableLog,
            disableWarnings: disableWarnings
        };

        // Shim browser if found.
        switch (browserDetails.browser) {
            case 'chrome':
                if (!chromeShim || !shimPeerConnection$2 ||
                    !options.shimChrome) {
                    logging('Chrome shim is not included in this adapter release.');
                    return adapter;
                }
                if (browserDetails.version === null) {
                    logging('Chrome shim can not determine version, not shimming.');
                    return adapter;
                }
                logging('adapter.js shimming chrome.');
                // Export to the adapter global object visible in the browser.
                adapter.browserShim = chromeShim;

                // Must be called before shimPeerConnection.
                shimAddIceCandidateNullOrEmpty(window, browserDetails);

                shimGetUserMedia$3(window, browserDetails);
                shimMediaStream(window);
                shimPeerConnection$2(window, browserDetails);
                shimOnTrack$1(window);
                shimAddTrackRemoveTrack(window, browserDetails);
                shimGetSendersWithDtmf(window);
                shimGetStats(window);
                shimSenderReceiverGetStats(window);
                fixNegotiationNeeded(window, browserDetails);

                shimRTCIceCandidate(window);
                shimConnectionState(window);
                shimMaxMessageSize(window, browserDetails);
                shimSendThrowTypeError(window);
                removeExtmapAllowMixed(window, browserDetails);
                break;
            case 'firefox':
                if (!firefoxShim || !shimPeerConnection ||
                    !options.shimFirefox) {
                    logging('Firefox shim is not included in this adapter release.');
                    return adapter;
                }
                logging('adapter.js shimming firefox.');
                // Export to the adapter global object visible in the browser.
                adapter.browserShim = firefoxShim;

                // Must be called before shimPeerConnection.
                shimAddIceCandidateNullOrEmpty(window, browserDetails);

                shimGetUserMedia$1(window, browserDetails);
                shimPeerConnection(window, browserDetails);
                shimOnTrack(window);
                shimRemoveStream(window);
                shimSenderGetStats(window);
                shimReceiverGetStats(window);
                shimRTCDataChannel(window);
                shimAddTransceiver(window);
                shimGetParameters(window);
                shimCreateOffer(window);
                shimCreateAnswer(window);

                shimRTCIceCandidate(window);
                shimConnectionState(window);
                shimMaxMessageSize(window, browserDetails);
                shimSendThrowTypeError(window);
                break;
            case 'edge':
                if (!edgeShim || !shimPeerConnection$1 || !options.shimEdge) {
                    logging('MS edge shim is not included in this adapter release.');
                    return adapter;
                }
                logging('adapter.js shimming edge.');
                // Export to the adapter global object visible in the browser.
                adapter.browserShim = edgeShim;

                shimGetUserMedia$2(window);
                shimGetDisplayMedia$1(window);
                shimPeerConnection$1(window, browserDetails);
                shimReplaceTrack(window);

                // the edge shim implements the full RTCIceCandidate object.

                shimMaxMessageSize(window, browserDetails);
                shimSendThrowTypeError(window);
                break;
            case 'safari':
                if (!safariShim || !options.shimSafari) {
                    logging('Safari shim is not included in this adapter release.');
                    return adapter;
                }
                logging('adapter.js shimming safari.');
                // Export to the adapter global object visible in the browser.
                adapter.browserShim = safariShim;

                // Must be called before shimCallbackAPI.
                shimAddIceCandidateNullOrEmpty(window, browserDetails);

                shimRTCIceServerUrls(window);
                shimCreateOfferLegacy(window);
                shimCallbacksAPI(window);
                shimLocalStreamsAPI(window);
                shimRemoteStreamsAPI(window);
                shimTrackEventTransceiver(window);
                shimGetUserMedia(window);
                shimAudioContext(window);

                shimRTCIceCandidate(window);
                shimMaxMessageSize(window, browserDetails);
                shimSendThrowTypeError(window);
                removeExtmapAllowMixed(window, browserDetails);
                break;
            default:
                logging('Unsupported browser!');
                break;
        }

        return adapter;
    }

    /*
	 *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
	 *
	 *  Use of this source code is governed by a BSD-style license
	 *  that can be found in the LICENSE file in the root of the source
	 *  tree.
	 */

    adapterFactory({window: typeof window === 'undefined' ? undefined : window});

    /**
     * @class AudioTrackConstraints
     * @classDesc Constraints for creating an audio MediaStreamTrack.
     * @memberof Owt.Base
     * @constructor
     * @param {Owt.Base.AudioSourceInfo} source Source info of this audio track.
     */
    class AudioTrackConstraints {
        // eslint-disable-next-line require-jsdoc
        constructor(source) {
            if (!Object.values(AudioSourceInfo).some(v => v === source)) {
                throw new TypeError('Invalid source.');
            }
            /**
             * @member {string} source
             * @memberof Owt.Base.AudioTrackConstraints
             * @desc Values could be "mic", "screen-cast", "file" or "mixed".
             * @instance
             */
            this.source = source;
            /**
             * @member {string} deviceId
             * @memberof Owt.Base.AudioTrackConstraints
             * @desc Do not provide deviceId if source is not "mic".
             * @instance
             * @see https://w3c.github.io/mediacapture-main/#def-constraint-deviceId
             */
            this.deviceId = undefined;
        }
    }

    /**
     * @class VideoTrackConstraints
     * @classDesc Constraints for creating a video MediaStreamTrack.
     * @memberof Owt.Base
     * @constructor
     * @param {Owt.Base.VideoSourceInfo} source Source info of this video track.
     */
    class VideoTrackConstraints {
        // eslint-disable-next-line require-jsdoc
        constructor(source) {
            if (!Object.values(VideoSourceInfo).some(v => v === source)) {
                throw new TypeError('Invalid source.');
            }
            /**
             * @member {string} source
             * @memberof Owt.Base.VideoTrackConstraints
             * @desc Values could be "camera", "screen-cast", "file" or "mixed".
             * @instance
             */
            this.source = source;
            /**
             * @member {string} deviceId
             * @memberof Owt.Base.VideoTrackConstraints
             * @desc Do not provide deviceId if source is not "camera".
             * @instance
             * @see https://w3c.github.io/mediacapture-main/#def-constraint-deviceId
             */

            this.deviceId = undefined;

            /**
             * @member {Owt.Base.Resolution} resolution
             * @memberof Owt.Base.VideoTrackConstraints
             * @instance
             */
            this.resolution = undefined;

            /**
             * @member {number} frameRate
             * @memberof Owt.Base.VideoTrackConstraints
             * @instance
             */
            this.frameRate = undefined;
        }
    }

    /**
     * @class StreamConstraints
     * @classDesc Constraints for creating a MediaStream from screen mic and camera.
     * @memberof Owt.Base
     * @constructor
     * @param {?Owt.Base.AudioTrackConstraints} audioConstraints
     * @param {?Owt.Base.VideoTrackConstraints} videoConstraints
     */
    class StreamConstraints {
        // eslint-disable-next-line require-jsdoc
        constructor(audioConstraints = false, videoConstraints = false) {
            /**
             * @member {Owt.Base.MediaStreamTrackDeviceConstraintsForAudio} audio
             * @memberof Owt.Base.MediaStreamDeviceConstraints
             * @instance
             */
            this.audio = audioConstraints;
            /**
             * @member {Owt.Base.MediaStreamTrackDeviceConstraintsForVideo} Video
             * @memberof Owt.Base.MediaStreamDeviceConstraints
             * @instance
             */
            this.video = videoConstraints;
        }
    }

    // eslint-disable-next-line require-jsdoc
    function isVideoConstrainsForScreenCast(constraints) {
        return typeof constraints.video === 'object' && constraints.video.source === VideoSourceInfo.SCREENCAST;
    }

    /**
     * @class MediaStreamFactory
     * @classDesc A factory to create MediaStream. You can also create MediaStream by yourself.
     * @memberof Owt.Base
     */
    class MediaStreamFactory {
        /**
         * @function createMediaStream
         * @static
         * @desc Create a MediaStream with given constraints. If you want to create a MediaStream for screen cast, please make sure both audio and video's source are "screen-cast".
         * @memberof Owt.Base.MediaStreamFactory
         * @return {Promise<MediaStream, Error>} Return a promise that is resolved when stream is successfully created, or rejected if one of the following error happened:
         * - One or more parameters cannot be satisfied.
         * - Specified device is busy.
         * - Cannot obtain necessary permission or operation is canceled by user.
         * - Video source is screen cast, while audio source is not.
         * - Audio source is screen cast, while video source is disabled.
         * @param {Owt.Base.StreamConstraints} constraints
         */
        static createMediaStream(constraints) {
            if (typeof constraints !== 'object' || !constraints.audio && !constraints.video) {
                return Promise.reject(new TypeError('Invalid constrains'));
            }
            if (!isVideoConstrainsForScreenCast(constraints) && typeof constraints.audio === 'object' && constraints.audio.source === AudioSourceInfo.SCREENCAST) {
                return Promise.reject(new TypeError('Cannot share screen without video.'));
            }
            if (isVideoConstrainsForScreenCast(constraints) && !isChrome() && !isFirefox()) {
                return Promise.reject(new TypeError('Screen sharing only supports Chrome and Firefox.'));
            }
            if (isVideoConstrainsForScreenCast(constraints) && typeof constraints.audio === 'object' && constraints.audio.source !== AudioSourceInfo.SCREENCAST) {
                return Promise.reject(new TypeError('Cannot capture video from screen cast while capture audio from' + ' other source.'));
            }

            // Check and convert constraints.
            if (!constraints.audio && !constraints.video) {
                return Promise.reject(new TypeError('At least one of audio and video must be requested.'));
            }
            const mediaConstraints = Object.create({});
            if (typeof constraints.audio === 'object' && constraints.audio.source === AudioSourceInfo.MIC) {
                mediaConstraints.audio = Object.create({});
                if (isEdge()) {
                    mediaConstraints.audio.deviceId = constraints.audio.deviceId;
                } else {
                    mediaConstraints.audio.deviceId = {
                        exact: constraints.audio.deviceId
                    };
                }
            } else {
                if (constraints.audio.source === AudioSourceInfo.SCREENCAST) {
                    mediaConstraints.audio = true;
                } else {
                    mediaConstraints.audio = constraints.audio;
                }
            }
            if (typeof constraints.video === 'object') {
                mediaConstraints.video = Object.create({});
                if (typeof constraints.video.frameRate === 'number') {
                    mediaConstraints.video.frameRate = constraints.video.frameRate;
                }
                if (constraints.video.resolution && constraints.video.resolution.width && constraints.video.resolution.height) {
                    if (constraints.video.source === VideoSourceInfo.SCREENCAST) {
                        mediaConstraints.video.width = constraints.video.resolution.width;
                        mediaConstraints.video.height = constraints.video.resolution.height;
                    } else {
                        mediaConstraints.video.width = Object.create({});
                        mediaConstraints.video.width.exact = constraints.video.resolution.width;
                        mediaConstraints.video.height = Object.create({});
                        mediaConstraints.video.height.exact = constraints.video.resolution.height;
                    }
                }
                if (typeof constraints.video.deviceId === 'string') {
                    mediaConstraints.video.deviceId = {
                        exact: constraints.video.deviceId
                    };
                }
                if (isFirefox() && constraints.video.source === VideoSourceInfo.SCREENCAST) {
                    mediaConstraints.video.mediaSource = 'screen';
                }
            } else {
                mediaConstraints.video = constraints.video;
            }
            if (isVideoConstrainsForScreenCast(constraints)) {
                return navigator.mediaDevices.getDisplayMedia(mediaConstraints);
            } else {
                return navigator.mediaDevices.getUserMedia(mediaConstraints);
            }
        }
    }

    // Copyright (C) <2018> Intel Corporation

    var media = /*#__PURE__*/Object.freeze({
        __proto__: null,
        AudioTrackConstraints: AudioTrackConstraints,
        VideoTrackConstraints: VideoTrackConstraints,
        StreamConstraints: StreamConstraints,
        MediaStreamFactory: MediaStreamFactory,
        AudioSourceInfo: AudioSourceInfo,
        VideoSourceInfo: VideoSourceInfo,
        TrackKind: TrackKind,
        Resolution: Resolution
    });

    let logger;
    let errorLogger;

    function setLogger() {
        /*eslint-disable */
        logger = console.log;
        errorLogger = console.error;
        /*eslint-enable */
    }

    function log(message, ...optionalParams) {
        if (logger) {
            logger(message, ...optionalParams);
        }
    }

    function error(message, ...optionalParams) {
        if (errorLogger) {
            errorLogger(message, ...optionalParams);
        }
    }

    class Event$1 {
        constructor(type) {
            this.listener = {};
            this.type = type | '';
        }

        on(event, fn) {
            if (!this.listener[event]) {
                this.listener[event] = [];
            }
            this.listener[event].push(fn);
            return true;
        }

        off(event, fn) {
            if (this.listener[event]) {
                var index = this.listener[event].indexOf(fn);
                if (index > -1) {
                    this.listener[event].splice(index, 1);
                }
                return true;
            }
            return false;
        }

        offAll() {
            this.listener = {};
        }

        dispatch(event, data) {
            if (this.listener[event]) {
                this.listener[event].map(each => {
                    each.apply(null, [data]);
                });
                return true;
            }
            return false;
        }
    }

    var bind = function bind(fn, thisArg) {
        return function wrap() {
            var args = new Array(arguments.length);
            for (var i = 0; i < args.length; i++) {
                args[i] = arguments[i];
            }
            return fn.apply(thisArg, args);
        };
    };

    // utils is a library of generic helper functions non-specific to axios

    var toString = Object.prototype.toString;

    // eslint-disable-next-line func-names
    var kindOf = (function (cache) {
        // eslint-disable-next-line func-names
        return function (thing) {
            var str = toString.call(thing);
            return cache[str] || (cache[str] = str.slice(8, -1).toLowerCase());
        };
    })(Object.create(null));

    function kindOfTest(type) {
        type = type.toLowerCase();
        return function isKindOf(thing) {
            return kindOf(thing) === type;
        };
    }

    /**
     * Determine if a value is an Array
     *
     * @param {Object} val The value to test
     * @returns {boolean} True if value is an Array, otherwise false
     */
    function isArray(val) {
        return Array.isArray(val);
    }

    /**
     * Determine if a value is undefined
     *
     * @param {Object} val The value to test
     * @returns {boolean} True if the value is undefined, otherwise false
     */
    function isUndefined(val) {
        return typeof val === 'undefined';
    }

    /**
     * Determine if a value is a Buffer
     *
     * @param {Object} val The value to test
     * @returns {boolean} True if value is a Buffer, otherwise false
     */
    function isBuffer(val) {
        return val !== null && !isUndefined(val) && val.constructor !== null && !isUndefined(val.constructor)
            && typeof val.constructor.isBuffer === 'function' && val.constructor.isBuffer(val);
    }

    /**
     * Determine if a value is an ArrayBuffer
     *
     * @function
     * @param {Object} val The value to test
     * @returns {boolean} True if value is an ArrayBuffer, otherwise false
     */
    var isArrayBuffer = kindOfTest('ArrayBuffer');


    /**
     * Determine if a value is a view on an ArrayBuffer
     *
     * @param {Object} val The value to test
     * @returns {boolean} True if value is a view on an ArrayBuffer, otherwise false
     */
    function isArrayBufferView(val) {
        var result;
        if ((typeof ArrayBuffer !== 'undefined') && (ArrayBuffer.isView)) {
            result = ArrayBuffer.isView(val);
        } else {
            result = (val) && (val.buffer) && (isArrayBuffer(val.buffer));
        }
        return result;
    }

    /**
     * Determine if a value is a String
     *
     * @param {Object} val The value to test
     * @returns {boolean} True if value is a String, otherwise false
     */
    function isString(val) {
        return typeof val === 'string';
    }

    /**
     * Determine if a value is a Number
     *
     * @param {Object} val The value to test
     * @returns {boolean} True if value is a Number, otherwise false
     */
    function isNumber(val) {
        return typeof val === 'number';
    }

    /**
     * Determine if a value is an Object
     *
     * @param {Object} val The value to test
     * @returns {boolean} True if value is an Object, otherwise false
     */
    function isObject(val) {
        return val !== null && typeof val === 'object';
    }

    /**
     * Determine if a value is a plain Object
     *
     * @param {Object} val The value to test
     * @return {boolean} True if value is a plain Object, otherwise false
     */
    function isPlainObject(val) {
        if (kindOf(val) !== 'object') {
            return false;
        }

        var prototype = Object.getPrototypeOf(val);
        return prototype === null || prototype === Object.prototype;
    }

    /**
     * Determine if a value is a Date
     *
     * @function
     * @param {Object} val The value to test
     * @returns {boolean} True if value is a Date, otherwise false
     */
    var isDate = kindOfTest('Date');

    /**
     * Determine if a value is a File
     *
     * @function
     * @param {Object} val The value to test
     * @returns {boolean} True if value is a File, otherwise false
     */
    var isFile = kindOfTest('File');

    /**
     * Determine if a value is a Blob
     *
     * @function
     * @param {Object} val The value to test
     * @returns {boolean} True if value is a Blob, otherwise false
     */
    var isBlob = kindOfTest('Blob');

    /**
     * Determine if a value is a FileList
     *
     * @function
     * @param {Object} val The value to test
     * @returns {boolean} True if value is a File, otherwise false
     */
    var isFileList = kindOfTest('FileList');

    /**
     * Determine if a value is a Function
     *
     * @param {Object} val The value to test
     * @returns {boolean} True if value is a Function, otherwise false
     */
    function isFunction(val) {
        return toString.call(val) === '[object Function]';
    }

    /**
     * Determine if a value is a Stream
     *
     * @param {Object} val The value to test
     * @returns {boolean} True if value is a Stream, otherwise false
     */
    function isStream(val) {
        return isObject(val) && isFunction(val.pipe);
    }

    /**
     * Determine if a value is a FormData
     *
     * @param {Object} thing The value to test
     * @returns {boolean} True if value is an FormData, otherwise false
     */
    function isFormData(thing) {
        var pattern = '[object FormData]';
        return thing && (
            (typeof FormData === 'function' && thing instanceof FormData) ||
            toString.call(thing) === pattern ||
            (isFunction(thing.toString) && thing.toString() === pattern)
        );
    }

    /**
     * Determine if a value is a URLSearchParams object
     * @function
     * @param {Object} val The value to test
     * @returns {boolean} True if value is a URLSearchParams object, otherwise false
     */
    var isURLSearchParams = kindOfTest('URLSearchParams');

    /**
     * Trim excess whitespace off the beginning and end of a string
     *
     * @param {String} str The String to trim
     * @returns {String} The String freed of excess whitespace
     */
    function trim(str) {
        return str.trim ? str.trim() : str.replace(/^\s+|\s+$/g, '');
    }

    /**
     * Determine if we're running in a standard browser environment
     *
     * This allows axios to run in a web worker, and react-native.
     * Both environments support XMLHttpRequest, but not fully standard globals.
     *
     * web workers:
     *  typeof window -> undefined
     *  typeof document -> undefined
     *
     * react-native:
     *  navigator.product -> 'ReactNative'
     * nativescript
     *  navigator.product -> 'NativeScript' or 'NS'
     */
    function isStandardBrowserEnv() {
        if (typeof navigator !== 'undefined' && (navigator.product === 'ReactNative' ||
            navigator.product === 'NativeScript' ||
            navigator.product === 'NS')) {
            return false;
        }
        return (
            typeof window !== 'undefined' &&
            typeof document !== 'undefined'
        );
    }

    /**
     * Iterate over an Array or an Object invoking a function for each item.
     *
     * If `obj` is an Array callback will be called passing
     * the value, index, and complete array for each item.
     *
     * If 'obj' is an Object callback will be called passing
     * the value, key, and complete object for each property.
     *
     * @param {Object|Array} obj The object to iterate
     * @param {Function} fn The callback to invoke for each item
     */
    function forEach(obj, fn) {
        // Don't bother if no value provided
        if (obj === null || typeof obj === 'undefined') {
            return;
        }

        // Force an array if not already something iterable
        if (typeof obj !== 'object') {
            /*eslint no-param-reassign:0*/
            obj = [obj];
        }

        if (isArray(obj)) {
            // Iterate over array values
            for (var i = 0, l = obj.length; i < l; i++) {
                fn.call(null, obj[i], i, obj);
            }
        } else {
            // Iterate over object keys
            for (var key in obj) {
                if (Object.prototype.hasOwnProperty.call(obj, key)) {
                    fn.call(null, obj[key], key, obj);
                }
            }
        }
    }

    /**
     * Accepts varargs expecting each argument to be an object, then
     * immutably merges the properties of each object and returns result.
     *
     * When multiple objects contain the same key the later object in
     * the arguments list will take precedence.
     *
     * Example:
     *
     * ```js
     * var result = merge({foo: 123}, {foo: 456});
     * console.log(result.foo); // outputs 456
     * ```
     *
     * @param {Object} obj1 Object to merge
     * @returns {Object} Result of all merge properties
     */
    function merge(/* obj1, obj2, obj3, ... */) {
        var result = {};

        function assignValue(val, key) {
            if (isPlainObject(result[key]) && isPlainObject(val)) {
                result[key] = merge(result[key], val);
            } else if (isPlainObject(val)) {
                result[key] = merge({}, val);
            } else if (isArray(val)) {
                result[key] = val.slice();
            } else {
                result[key] = val;
            }
        }

        for (var i = 0, l = arguments.length; i < l; i++) {
            forEach(arguments[i], assignValue);
        }
        return result;
    }

    /**
     * Extends object a by mutably adding to it the properties of object b.
     *
     * @param {Object} a The object to be extended
     * @param {Object} b The object to copy properties from
     * @param {Object} thisArg The object to bind function to
     * @return {Object} The resulting value of object a
     */
    function extend(a, b, thisArg) {
        forEach(b, function assignValue(val, key) {
            if (thisArg && typeof val === 'function') {
                a[key] = bind(val, thisArg);
            } else {
                a[key] = val;
            }
        });
        return a;
    }

    /**
     * Remove byte order marker. This catches EF BB BF (the UTF-8 BOM)
     *
     * @param {string} content with BOM
     * @return {string} content value without BOM
     */
    function stripBOM(content) {
        if (content.charCodeAt(0) === 0xFEFF) {
            content = content.slice(1);
        }
        return content;
    }

    /**
     * Inherit the prototype methods from one constructor into another
     * @param {function} constructor
     * @param {function} superConstructor
     * @param {object} [props]
     * @param {object} [descriptors]
     */

    function inherits(constructor, superConstructor, props, descriptors) {
        constructor.prototype = Object.create(superConstructor.prototype, descriptors);
        constructor.prototype.constructor = constructor;
        props && Object.assign(constructor.prototype, props);
    }

    /**
     * Resolve object with deep prototype chain to a flat object
     * @param {Object} sourceObj source object
     * @param {Object} [destObj]
     * @param {Function} [filter]
     * @returns {Object}
     */

    function toFlatObject(sourceObj, destObj, filter) {
        var props;
        var i;
        var prop;
        var merged = {};

        destObj = destObj || {};

        do {
            props = Object.getOwnPropertyNames(sourceObj);
            i = props.length;
            while (i-- > 0) {
                prop = props[i];
                if (!merged[prop]) {
                    destObj[prop] = sourceObj[prop];
                    merged[prop] = true;
                }
            }
            sourceObj = Object.getPrototypeOf(sourceObj);
        } while (sourceObj && (!filter || filter(sourceObj, destObj)) && sourceObj !== Object.prototype);

        return destObj;
    }

    /*
	 * determines whether a string ends with the characters of a specified string
	 * @param {String} str
	 * @param {String} searchString
	 * @param {Number} [position= 0]
	 * @returns {boolean}
	 */
    function endsWith(str, searchString, position) {
        str = String(str);
        if (position === undefined || position > str.length) {
            position = str.length;
        }
        position -= searchString.length;
        var lastIndex = str.indexOf(searchString, position);
        return lastIndex !== -1 && lastIndex === position;
    }


    /**
     * Returns new array from array like object
     * @param {*} [thing]
     * @returns {Array}
     */
    function toArray(thing) {
        if (!thing) return null;
        var i = thing.length;
        if (isUndefined(i)) return null;
        var arr = new Array(i);
        while (i-- > 0) {
            arr[i] = thing[i];
        }
        return arr;
    }

    // eslint-disable-next-line func-names
    var isTypedArray = (function (TypedArray) {
        // eslint-disable-next-line func-names
        return function (thing) {
            return TypedArray && thing instanceof TypedArray;
        };
    })(typeof Uint8Array !== 'undefined' && Object.getPrototypeOf(Uint8Array));

    var utils = {
        isArray: isArray,
        isArrayBuffer: isArrayBuffer,
        isBuffer: isBuffer,
        isFormData: isFormData,
        isArrayBufferView: isArrayBufferView,
        isString: isString,
        isNumber: isNumber,
        isObject: isObject,
        isPlainObject: isPlainObject,
        isUndefined: isUndefined,
        isDate: isDate,
        isFile: isFile,
        isBlob: isBlob,
        isFunction: isFunction,
        isStream: isStream,
        isURLSearchParams: isURLSearchParams,
        isStandardBrowserEnv: isStandardBrowserEnv,
        forEach: forEach,
        merge: merge,
        extend: extend,
        trim: trim,
        stripBOM: stripBOM,
        inherits: inherits,
        toFlatObject: toFlatObject,
        kindOf: kindOf,
        kindOfTest: kindOfTest,
        endsWith: endsWith,
        toArray: toArray,
        isTypedArray: isTypedArray,
        isFileList: isFileList
    };

    function encode(val) {
        return encodeURIComponent(val).replace(/%3A/gi, ':').replace(/%24/g, '$').replace(/%2C/gi, ',').replace(/%20/g, '+').replace(/%5B/gi, '[').replace(/%5D/gi, ']');
    }

    /**
     * Build a URL by appending params to the end
     *
     * @param {string} url The base of the url (e.g., http://www.google.com)
     * @param {object} [params] The params to be appended
     * @returns {string} The formatted url
     */
    var buildURL = function buildURL(url, params, paramsSerializer) {
        /*eslint no-param-reassign:0*/
        if (!params) {
            return url;
        }

        var serializedParams;
        if (paramsSerializer) {
            serializedParams = paramsSerializer(params);
        } else if (utils.isURLSearchParams(params)) {
            serializedParams = params.toString();
        } else {
            var parts = [];

            utils.forEach(params, function serialize(val, key) {
                if (val === null || typeof val === 'undefined') {
                    return;
                }

                if (utils.isArray(val)) {
                    key = key + '[]';
                } else {
                    val = [val];
                }

                utils.forEach(val, function parseValue(v) {
                    if (utils.isDate(v)) {
                        v = v.toISOString();
                    } else if (utils.isObject(v)) {
                        v = JSON.stringify(v);
                    }
                    parts.push(encode(key) + '=' + encode(v));
                });
            });

            serializedParams = parts.join('&');
        }

        if (serializedParams) {
            var hashmarkIndex = url.indexOf('#');
            if (hashmarkIndex !== -1) {
                url = url.slice(0, hashmarkIndex);
            }

            url += (url.indexOf('?') === -1 ? '?' : '&') + serializedParams;
        }

        return url;
    };

    function InterceptorManager() {
        this.handlers = [];
    }

    /**
     * Add a new interceptor to the stack
     *
     * @param {Function} fulfilled The function to handle `then` for a `Promise`
     * @param {Function} rejected The function to handle `reject` for a `Promise`
     *
     * @return {Number} An ID used to remove interceptor later
     */
    InterceptorManager.prototype.use = function use(fulfilled, rejected, options) {
        this.handlers.push({
            fulfilled: fulfilled,
            rejected: rejected,
            synchronous: options ? options.synchronous : false,
            runWhen: options ? options.runWhen : null
        });
        return this.handlers.length - 1;
    };

    /**
     * Remove an interceptor from the stack
     *
     * @param {Number} id The ID that was returned by `use`
     */
    InterceptorManager.prototype.eject = function eject(id) {
        if (this.handlers[id]) {
            this.handlers[id] = null;
        }
    };

    /**
     * Iterate over all the registered interceptors
     *
     * This method is particularly useful for skipping over any
     * interceptors that may have become `null` calling `eject`.
     *
     * @param {Function} fn The function to call for each interceptor
     */
    InterceptorManager.prototype.forEach = function forEach(fn) {
        utils.forEach(this.handlers, function forEachHandler(h) {
            if (h !== null) {
                fn(h);
            }
        });
    };

    var InterceptorManager_1 = InterceptorManager;

    var normalizeHeaderName = function normalizeHeaderName(headers, normalizedName) {
        utils.forEach(headers, function processHeader(value, name) {
            if (name !== normalizedName && name.toUpperCase() === normalizedName.toUpperCase()) {
                headers[normalizedName] = value;
                delete headers[name];
            }
        });
    };

    /**
     * Create an Error with the specified message, config, error code, request and response.
     *
     * @param {string} message The error message.
     * @param {string} [code] The error code (for example, 'ECONNABORTED').
     * @param {Object} [config] The config.
     * @param {Object} [request] The request.
     * @param {Object} [response] The response.
     * @returns {Error} The created error.
     */
    function AxiosError(message, code, config, request, response) {
        Error.call(this);
        this.message = message;
        this.name = 'AxiosError';
        code && (this.code = code);
        config && (this.config = config);
        request && (this.request = request);
        response && (this.response = response);
    }

    utils.inherits(AxiosError, Error, {
        toJSON: function toJSON() {
            return {
                // Standard
                message: this.message,
                name: this.name,
                // Microsoft
                description: this.description,
                number: this.number,
                // Mozilla
                fileName: this.fileName,
                lineNumber: this.lineNumber,
                columnNumber: this.columnNumber,
                stack: this.stack,
                // Axios
                config: this.config,
                code: this.code,
                status: this.response && this.response.status ? this.response.status : null
            };
        }
    });

    var prototype = AxiosError.prototype;
    var descriptors = {};

    [
        'ERR_BAD_OPTION_VALUE',
        'ERR_BAD_OPTION',
        'ECONNABORTED',
        'ETIMEDOUT',
        'ERR_NETWORK',
        'ERR_FR_TOO_MANY_REDIRECTS',
        'ERR_DEPRECATED',
        'ERR_BAD_RESPONSE',
        'ERR_BAD_REQUEST',
        'ERR_CANCELED'
        // eslint-disable-next-line func-names
    ].forEach(function (code) {
        descriptors[code] = {value: code};
    });

    Object.defineProperties(AxiosError, descriptors);
    Object.defineProperty(prototype, 'isAxiosError', {value: true});

    // eslint-disable-next-line func-names
    AxiosError.from = function (error, code, config, request, response, customProps) {
        var axiosError = Object.create(prototype);

        utils.toFlatObject(error, axiosError, function filter(obj) {
            return obj !== Error.prototype;
        });

        AxiosError.call(axiosError, error.message, code, config, request, response);

        axiosError.name = error.name;

        customProps && Object.assign(axiosError, customProps);

        return axiosError;
    };

    var AxiosError_1 = AxiosError;

    var transitional = {
        silentJSONParsing: true,
        forcedJSONParsing: true,
        clarifyTimeoutError: false
    };

    /**
     * Convert a data object to FormData
     * @param {Object} obj
     * @param {?Object} [formData]
     * @returns {Object}
     **/

    function toFormData(obj, formData) {
        // eslint-disable-next-line no-param-reassign
        formData = formData || new FormData();

        var stack = [];

        function convertValue(value) {
            if (value === null) return '';

            if (utils.isDate(value)) {
                return value.toISOString();
            }

            if (utils.isArrayBuffer(value) || utils.isTypedArray(value)) {
                return typeof Blob === 'function' ? new Blob([value]) : Buffer.from(value);
            }

            return value;
        }

        function build(data, parentKey) {
            if (utils.isPlainObject(data) || utils.isArray(data)) {
                if (stack.indexOf(data) !== -1) {
                    throw Error('Circular reference detected in ' + parentKey);
                }

                stack.push(data);

                utils.forEach(data, function each(value, key) {
                    if (utils.isUndefined(value)) return;
                    var fullKey = parentKey ? parentKey + '.' + key : key;
                    var arr;

                    if (value && !parentKey && typeof value === 'object') {
                        if (utils.endsWith(key, '{}')) {
                            // eslint-disable-next-line no-param-reassign
                            value = JSON.stringify(value);
                        } else if (utils.endsWith(key, '[]') && (arr = utils.toArray(value))) {
                            // eslint-disable-next-line func-names
                            arr.forEach(function (el) {
                                !utils.isUndefined(el) && formData.append(fullKey, convertValue(el));
                            });
                            return;
                        }
                    }

                    build(value, fullKey);
                });

                stack.pop();
            } else {
                formData.append(parentKey, convertValue(data));
            }
        }

        build(obj);

        return formData;
    }

    var toFormData_1 = toFormData;

    /**
     * Resolve or reject a Promise based on response status.
     *
     * @param {Function} resolve A function that resolves the promise.
     * @param {Function} reject A function that rejects the promise.
     * @param {object} response The response.
     */
    var settle = function settle(resolve, reject, response) {
        var validateStatus = response.config.validateStatus;
        if (!response.status || !validateStatus || validateStatus(response.status)) {
            resolve(response);
        } else {
            reject(new AxiosError_1(
                'Request failed with status code ' + response.status,
                [AxiosError_1.ERR_BAD_REQUEST, AxiosError_1.ERR_BAD_RESPONSE][Math.floor(response.status / 100) - 4],
                response.config,
                response.request,
                response
            ));
        }
    };

    var cookies = (
        utils.isStandardBrowserEnv() ?

            // Standard browser envs support document.cookie
            (function standardBrowserEnv() {
                return {
                    write: function write(name, value, expires, path, domain, secure) {
                        var cookie = [];
                        cookie.push(name + '=' + encodeURIComponent(value));

                        if (utils.isNumber(expires)) {
                            cookie.push('expires=' + new Date(expires).toGMTString());
                        }

                        if (utils.isString(path)) {
                            cookie.push('path=' + path);
                        }

                        if (utils.isString(domain)) {
                            cookie.push('domain=' + domain);
                        }

                        if (secure === true) {
                            cookie.push('secure');
                        }

                        document.cookie = cookie.join('; ');
                    },

                    read: function read(name) {
                        var match = document.cookie.match(new RegExp('(^|;\\s*)(' + name + ')=([^;]*)'));
                        return (match ? decodeURIComponent(match[3]) : null);
                    },

                    remove: function remove(name) {
                        this.write(name, '', Date.now() - 86400000);
                    }
                };
            })() :

            // Non standard browser env (web workers, react-native) lack needed support.
            (function nonStandardBrowserEnv() {
                return {
                    write: function write() {
                    },
                    read: function read() {
                        return null;
                    },
                    remove: function remove() {
                    }
                };
            })()
    );

    /**
     * Determines whether the specified URL is absolute
     *
     * @param {string} url The URL to test
     * @returns {boolean} True if the specified URL is absolute, otherwise false
     */
    var isAbsoluteURL = function isAbsoluteURL(url) {
        // A URL is considered absolute if it begins with "<scheme>://" or "//" (protocol-relative URL).
        // RFC 3986 defines scheme name as a sequence of characters beginning with a letter and followed
        // by any combination of letters, digits, plus, period, or hyphen.
        return /^([a-z][a-z\d+\-.]*:)?\/\//i.test(url);
    };

    /**
     * Creates a new URL by combining the specified URLs
     *
     * @param {string} baseURL The base URL
     * @param {string} relativeURL The relative URL
     * @returns {string} The combined URL
     */
    var combineURLs = function combineURLs(baseURL, relativeURL) {
        return relativeURL
            ? baseURL.replace(/\/+$/, '') + '/' + relativeURL.replace(/^\/+/, '')
            : baseURL;
    };

    /**
     * Creates a new URL by combining the baseURL with the requestedURL,
     * only when the requestedURL is not already an absolute URL.
     * If the requestURL is absolute, this function returns the requestedURL untouched.
     *
     * @param {string} baseURL The base URL
     * @param {string} requestedURL Absolute or relative URL to combine
     * @returns {string} The combined full path
     */
    var buildFullPath = function buildFullPath(baseURL, requestedURL) {
        if (baseURL && !isAbsoluteURL(requestedURL)) {
            return combineURLs(baseURL, requestedURL);
        }
        return requestedURL;
    };

    // Headers whose duplicates are ignored by node
    // c.f. https://nodejs.org/api/http.html#http_message_headers
    var ignoreDuplicateOf = [
        'age', 'authorization', 'content-length', 'content-type', 'etag',
        'expires', 'from', 'host', 'if-modified-since', 'if-unmodified-since',
        'last-modified', 'location', 'max-forwards', 'proxy-authorization',
        'referer', 'retry-after', 'user-agent'
    ];

    /**
     * Parse headers into an object
     *
     * ```
     * Date: Wed, 27 Aug 2014 08:58:49 GMT
     * Content-Type: application/json
     * Connection: keep-alive
     * Transfer-Encoding: chunked
     * ```
     *
     * @param {String} headers Headers needing to be parsed
     * @returns {Object} Headers parsed into an object
     */
    var parseHeaders = function parseHeaders(headers) {
        var parsed = {};
        var key;
        var val;
        var i;

        if (!headers) {
            return parsed;
        }

        utils.forEach(headers.split('\n'), function parser(line) {
            i = line.indexOf(':');
            key = utils.trim(line.substr(0, i)).toLowerCase();
            val = utils.trim(line.substr(i + 1));

            if (key) {
                if (parsed[key] && ignoreDuplicateOf.indexOf(key) >= 0) {
                    return;
                }
                if (key === 'set-cookie') {
                    parsed[key] = (parsed[key] ? parsed[key] : []).concat([val]);
                } else {
                    parsed[key] = parsed[key] ? parsed[key] + ', ' + val : val;
                }
            }
        });

        return parsed;
    };

    var isURLSameOrigin = (
        utils.isStandardBrowserEnv() ?

            // Standard browser envs have full support of the APIs needed to test
            // whether the request URL is of the same origin as current location.
            (function standardBrowserEnv() {
                var msie = /(msie|trident)/i.test(navigator.userAgent);
                var urlParsingNode = document.createElement('a');
                var originURL;

                /**
                 * Parse a URL to discover it's components
                 *
                 * @param {String} url The URL to be parsed
                 * @returns {Object}
                 */
                function resolveURL(url) {
                    var href = url;

                    if (msie) {
                        // IE needs attribute set twice to normalize properties
                        urlParsingNode.setAttribute('href', href);
                        href = urlParsingNode.href;
                    }

                    urlParsingNode.setAttribute('href', href);

                    // urlParsingNode provides the UrlUtils interface - http://url.spec.whatwg.org/#urlutils
                    return {
                        href: urlParsingNode.href,
                        protocol: urlParsingNode.protocol ? urlParsingNode.protocol.replace(/:$/, '') : '',
                        host: urlParsingNode.host,
                        search: urlParsingNode.search ? urlParsingNode.search.replace(/^\?/, '') : '',
                        hash: urlParsingNode.hash ? urlParsingNode.hash.replace(/^#/, '') : '',
                        hostname: urlParsingNode.hostname,
                        port: urlParsingNode.port,
                        pathname: (urlParsingNode.pathname.charAt(0) === '/') ?
                            urlParsingNode.pathname :
                            '/' + urlParsingNode.pathname
                    };
                }

                originURL = resolveURL(window.location.href);

                /**
                 * Determine if a URL shares the same origin as the current location
                 *
                 * @param {String} requestURL The URL to test
                 * @returns {boolean} True if URL shares the same origin, otherwise false
                 */
                return function isURLSameOrigin(requestURL) {
                    var parsed = (utils.isString(requestURL)) ? resolveURL(requestURL) : requestURL;
                    return (parsed.protocol === originURL.protocol &&
                        parsed.host === originURL.host);
                };
            })() :

            // Non standard browser envs (web workers, react-native) lack needed support.
            (function nonStandardBrowserEnv() {
                return function isURLSameOrigin() {
                    return true;
                };
            })()
    );

    /**
     * A `CanceledError` is an object that is thrown when an operation is canceled.
     *
     * @class
     * @param {string=} message The message.
     */
    function CanceledError(message) {
        // eslint-disable-next-line no-eq-null,eqeqeq
        AxiosError_1.call(this, message == null ? 'canceled' : message, AxiosError_1.ERR_CANCELED);
        this.name = 'CanceledError';
    }

    utils.inherits(CanceledError, AxiosError_1, {
        __CANCEL__: true
    });

    var CanceledError_1 = CanceledError;

    var parseProtocol = function parseProtocol(url) {
        var match = /^([-+\w]{1,25})(:?\/\/|:)/.exec(url);
        return match && match[1] || '';
    };

    var xhr = function xhrAdapter(config) {
        return new Promise(function dispatchXhrRequest(resolve, reject) {
            var requestData = config.data;
            var requestHeaders = config.headers;
            var responseType = config.responseType;
            var onCanceled;

            function done() {
                if (config.cancelToken) {
                    config.cancelToken.unsubscribe(onCanceled);
                }

                if (config.signal) {
                    config.signal.removeEventListener('abort', onCanceled);
                }
            }

            if (utils.isFormData(requestData) && utils.isStandardBrowserEnv()) {
                delete requestHeaders['Content-Type']; // Let the browser set it
            }

            var request = new XMLHttpRequest();

            // HTTP basic authentication
            if (config.auth) {
                var username = config.auth.username || '';
                var password = config.auth.password ? unescape(encodeURIComponent(config.auth.password)) : '';
                requestHeaders.Authorization = 'Basic ' + btoa(username + ':' + password);
            }

            var fullPath = buildFullPath(config.baseURL, config.url);

            request.open(config.method.toUpperCase(), buildURL(fullPath, config.params, config.paramsSerializer), true);

            // Set the request timeout in MS
            request.timeout = config.timeout;

            function onloadend() {
                if (!request) {
                    return;
                }
                // Prepare the response
                var responseHeaders = 'getAllResponseHeaders' in request ? parseHeaders(request.getAllResponseHeaders()) : null;
                var responseData = !responseType || responseType === 'text' || responseType === 'json' ?
                    request.responseText : request.response;
                var response = {
                    data: responseData,
                    status: request.status,
                    statusText: request.statusText,
                    headers: responseHeaders,
                    config: config,
                    request: request
                };

                settle(function _resolve(value) {
                    resolve(value);
                    done();
                }, function _reject(err) {
                    reject(err);
                    done();
                }, response);

                // Clean up request
                request = null;
            }

            if ('onloadend' in request) {
                // Use onloadend if available
                request.onloadend = onloadend;
            } else {
                // Listen for ready state to emulate onloadend
                request.onreadystatechange = function handleLoad() {
                    if (!request || request.readyState !== 4) {
                        return;
                    }

                    // The request errored out and we didn't get a response, this will be
                    // handled by onerror instead
                    // With one exception: request that using file: protocol, most browsers
                    // will return status as 0 even though it's a successful request
                    if (request.status === 0 && !(request.responseURL && request.responseURL.indexOf('file:') === 0)) {
                        return;
                    }
                    // readystate handler is calling before onerror or ontimeout handlers,
                    // so we should call onloadend on the next 'tick'
                    setTimeout(onloadend);
                };
            }

            // Handle browser request cancellation (as opposed to a manual cancellation)
            request.onabort = function handleAbort() {
                if (!request) {
                    return;
                }

                reject(new AxiosError_1('Request aborted', AxiosError_1.ECONNABORTED, config, request));

                // Clean up request
                request = null;
            };

            // Handle low level network errors
            request.onerror = function handleError() {
                // Real errors are hidden from us by the browser
                // onerror should only fire if it's a network error
                reject(new AxiosError_1('Network Error', AxiosError_1.ERR_NETWORK, config, request, request));

                // Clean up request
                request = null;
            };

            // Handle timeout
            request.ontimeout = function handleTimeout() {
                var timeoutErrorMessage = config.timeout ? 'timeout of ' + config.timeout + 'ms exceeded' : 'timeout exceeded';
                var transitional$1 = config.transitional || transitional;
                if (config.timeoutErrorMessage) {
                    timeoutErrorMessage = config.timeoutErrorMessage;
                }
                reject(new AxiosError_1(
                    timeoutErrorMessage,
                    transitional$1.clarifyTimeoutError ? AxiosError_1.ETIMEDOUT : AxiosError_1.ECONNABORTED,
                    config,
                    request));

                // Clean up request
                request = null;
            };

            // Add xsrf header
            // This is only done if running in a standard browser environment.
            // Specifically not if we're in a web worker, or react-native.
            if (utils.isStandardBrowserEnv()) {
                // Add xsrf header
                var xsrfValue = (config.withCredentials || isURLSameOrigin(fullPath)) && config.xsrfCookieName ?
                    cookies.read(config.xsrfCookieName) :
                    undefined;

                if (xsrfValue) {
                    requestHeaders[config.xsrfHeaderName] = xsrfValue;
                }
            }

            // Add headers to the request
            if ('setRequestHeader' in request) {
                utils.forEach(requestHeaders, function setRequestHeader(val, key) {
                    if (typeof requestData === 'undefined' && key.toLowerCase() === 'content-type') {
                        // Remove Content-Type if data is undefined
                        delete requestHeaders[key];
                    } else {
                        // Otherwise add header to the request
                        request.setRequestHeader(key, val);
                    }
                });
            }

            // Add withCredentials to request if needed
            if (!utils.isUndefined(config.withCredentials)) {
                request.withCredentials = !!config.withCredentials;
            }

            // Add responseType to request if needed
            if (responseType && responseType !== 'json') {
                request.responseType = config.responseType;
            }

            // Handle progress if needed
            if (typeof config.onDownloadProgress === 'function') {
                request.addEventListener('progress', config.onDownloadProgress);
            }

            // Not all browsers support upload events
            if (typeof config.onUploadProgress === 'function' && request.upload) {
                request.upload.addEventListener('progress', config.onUploadProgress);
            }

            if (config.cancelToken || config.signal) {
                // Handle cancellation
                // eslint-disable-next-line func-names
                onCanceled = function (cancel) {
                    if (!request) {
                        return;
                    }
                    reject(!cancel || (cancel && cancel.type) ? new CanceledError_1() : cancel);
                    request.abort();
                    request = null;
                };

                config.cancelToken && config.cancelToken.subscribe(onCanceled);
                if (config.signal) {
                    config.signal.aborted ? onCanceled() : config.signal.addEventListener('abort', onCanceled);
                }
            }

            if (!requestData) {
                requestData = null;
            }

            var protocol = parseProtocol(fullPath);

            if (protocol && ['http', 'https', 'file'].indexOf(protocol) === -1) {
                reject(new AxiosError_1('Unsupported protocol ' + protocol + ':', AxiosError_1.ERR_BAD_REQUEST, config));
                return;
            }


            // Send the request
            request.send(requestData);
        });
    };

    // eslint-disable-next-line strict
    var _null = null;

    var DEFAULT_CONTENT_TYPE = {
        'Content-Type': 'application/x-www-form-urlencoded'
    };

    function setContentTypeIfUnset(headers, value) {
        if (!utils.isUndefined(headers) && utils.isUndefined(headers['Content-Type'])) {
            headers['Content-Type'] = value;
        }
    }

    function getDefaultAdapter() {
        var adapter;
        if (typeof XMLHttpRequest !== 'undefined') {
            // For browsers use XHR adapter
            adapter = xhr;
        } else if (typeof process !== 'undefined' && Object.prototype.toString.call(process) === '[object process]') {
            // For node use HTTP adapter
            adapter = xhr;
        }
        return adapter;
    }

    function stringifySafely(rawValue, parser, encoder) {
        if (utils.isString(rawValue)) {
            try {
                (parser || JSON.parse)(rawValue);
                return utils.trim(rawValue);
            } catch (e) {
                if (e.name !== 'SyntaxError') {
                    throw e;
                }
            }
        }

        return (encoder || JSON.stringify)(rawValue);
    }

    var defaults = {

        transitional: transitional,

        adapter: getDefaultAdapter(),

        transformRequest: [function transformRequest(data, headers) {
            normalizeHeaderName(headers, 'Accept');
            normalizeHeaderName(headers, 'Content-Type');

            if (utils.isFormData(data) ||
                utils.isArrayBuffer(data) ||
                utils.isBuffer(data) ||
                utils.isStream(data) ||
                utils.isFile(data) ||
                utils.isBlob(data)
            ) {
                return data;
            }
            if (utils.isArrayBufferView(data)) {
                return data.buffer;
            }
            if (utils.isURLSearchParams(data)) {
                setContentTypeIfUnset(headers, 'application/x-www-form-urlencoded;charset=utf-8');
                return data.toString();
            }

            var isObjectPayload = utils.isObject(data);
            var contentType = headers && headers['Content-Type'];

            var isFileList;

            if ((isFileList = utils.isFileList(data)) || (isObjectPayload && contentType === 'multipart/form-data')) {
                var _FormData = this.env && this.env.FormData;
                return toFormData_1(isFileList ? {'files[]': data} : data, _FormData && new _FormData());
            } else if (isObjectPayload || contentType === 'application/json') {
                setContentTypeIfUnset(headers, 'application/json');
                return stringifySafely(data);
            }

            return data;
        }],

        transformResponse: [function transformResponse(data) {
            var transitional = this.transitional || defaults.transitional;
            var silentJSONParsing = transitional && transitional.silentJSONParsing;
            var forcedJSONParsing = transitional && transitional.forcedJSONParsing;
            var strictJSONParsing = !silentJSONParsing && this.responseType === 'json';

            if (strictJSONParsing || (forcedJSONParsing && utils.isString(data) && data.length)) {
                try {
                    return JSON.parse(data);
                } catch (e) {
                    if (strictJSONParsing) {
                        if (e.name === 'SyntaxError') {
                            throw AxiosError_1.from(e, AxiosError_1.ERR_BAD_RESPONSE, this, null, this.response);
                        }
                        throw e;
                    }
                }
            }

            return data;
        }],

        /**
         * A timeout in milliseconds to abort a request. If set to 0 (default) a
         * timeout is not created.
         */
        timeout: 0,

        xsrfCookieName: 'XSRF-TOKEN',
        xsrfHeaderName: 'X-XSRF-TOKEN',

        maxContentLength: -1,
        maxBodyLength: -1,

        env: {
            FormData: _null
        },

        validateStatus: function validateStatus(status) {
            return status >= 200 && status < 300;
        },

        headers: {
            common: {
                'Accept': 'application/json, text/plain, */*'
            }
        }
    };

    utils.forEach(['delete', 'get', 'head'], function forEachMethodNoData(method) {
        defaults.headers[method] = {};
    });

    utils.forEach(['post', 'put', 'patch'], function forEachMethodWithData(method) {
        defaults.headers[method] = utils.merge(DEFAULT_CONTENT_TYPE);
    });

    var defaults_1 = defaults;

    /**
     * Transform the data for a request or a response
     *
     * @param {Object|String} data The data to be transformed
     * @param {Array} headers The headers for the request or response
     * @param {Array|Function} fns A single function or Array of functions
     * @returns {*} The resulting transformed data
     */
    var transformData = function transformData(data, headers, fns) {
        var context = this || defaults_1;
        /*eslint no-param-reassign:0*/
        utils.forEach(fns, function transform(fn) {
            data = fn.call(context, data, headers);
        });

        return data;
    };

    var isCancel = function isCancel(value) {
        return !!(value && value.__CANCEL__);
    };

    /**
     * Throws a `CanceledError` if cancellation has been requested.
     */
    function throwIfCancellationRequested(config) {
        if (config.cancelToken) {
            config.cancelToken.throwIfRequested();
        }

        if (config.signal && config.signal.aborted) {
            throw new CanceledError_1();
        }
    }

    /**
     * Dispatch a request to the server using the configured adapter.
     *
     * @param {object} config The config that is to be used for the request
     * @returns {Promise} The Promise to be fulfilled
     */
    var dispatchRequest = function dispatchRequest(config) {
        throwIfCancellationRequested(config);

        // Ensure headers exist
        config.headers = config.headers || {};

        // Transform request data
        config.data = transformData.call(
            config,
            config.data,
            config.headers,
            config.transformRequest
        );

        // Flatten headers
        config.headers = utils.merge(
            config.headers.common || {},
            config.headers[config.method] || {},
            config.headers
        );

        utils.forEach(
            ['delete', 'get', 'head', 'post', 'put', 'patch', 'common'],
            function cleanHeaderConfig(method) {
                delete config.headers[method];
            }
        );

        var adapter = config.adapter || defaults_1.adapter;

        return adapter(config).then(function onAdapterResolution(response) {
            throwIfCancellationRequested(config);

            // Transform response data
            response.data = transformData.call(
                config,
                response.data,
                response.headers,
                config.transformResponse
            );

            return response;
        }, function onAdapterRejection(reason) {
            if (!isCancel(reason)) {
                throwIfCancellationRequested(config);

                // Transform response data
                if (reason && reason.response) {
                    reason.response.data = transformData.call(
                        config,
                        reason.response.data,
                        reason.response.headers,
                        config.transformResponse
                    );
                }
            }

            return Promise.reject(reason);
        });
    };

    /**
     * Config-specific merge-function which creates a new config-object
     * by merging two configuration objects together.
     *
     * @param {Object} config1
     * @param {Object} config2
     * @returns {Object} New object resulting from merging config2 to config1
     */
    var mergeConfig = function mergeConfig(config1, config2) {
        // eslint-disable-next-line no-param-reassign
        config2 = config2 || {};
        var config = {};

        function getMergedValue(target, source) {
            if (utils.isPlainObject(target) && utils.isPlainObject(source)) {
                return utils.merge(target, source);
            } else if (utils.isPlainObject(source)) {
                return utils.merge({}, source);
            } else if (utils.isArray(source)) {
                return source.slice();
            }
            return source;
        }

        // eslint-disable-next-line consistent-return
        function mergeDeepProperties(prop) {
            if (!utils.isUndefined(config2[prop])) {
                return getMergedValue(config1[prop], config2[prop]);
            } else if (!utils.isUndefined(config1[prop])) {
                return getMergedValue(undefined, config1[prop]);
            }
        }

        // eslint-disable-next-line consistent-return
        function valueFromConfig2(prop) {
            if (!utils.isUndefined(config2[prop])) {
                return getMergedValue(undefined, config2[prop]);
            }
        }

        // eslint-disable-next-line consistent-return
        function defaultToConfig2(prop) {
            if (!utils.isUndefined(config2[prop])) {
                return getMergedValue(undefined, config2[prop]);
            } else if (!utils.isUndefined(config1[prop])) {
                return getMergedValue(undefined, config1[prop]);
            }
        }

        // eslint-disable-next-line consistent-return
        function mergeDirectKeys(prop) {
            if (prop in config2) {
                return getMergedValue(config1[prop], config2[prop]);
            } else if (prop in config1) {
                return getMergedValue(undefined, config1[prop]);
            }
        }

        var mergeMap = {
            'url': valueFromConfig2,
            'method': valueFromConfig2,
            'data': valueFromConfig2,
            'baseURL': defaultToConfig2,
            'transformRequest': defaultToConfig2,
            'transformResponse': defaultToConfig2,
            'paramsSerializer': defaultToConfig2,
            'timeout': defaultToConfig2,
            'timeoutMessage': defaultToConfig2,
            'withCredentials': defaultToConfig2,
            'adapter': defaultToConfig2,
            'responseType': defaultToConfig2,
            'xsrfCookieName': defaultToConfig2,
            'xsrfHeaderName': defaultToConfig2,
            'onUploadProgress': defaultToConfig2,
            'onDownloadProgress': defaultToConfig2,
            'decompress': defaultToConfig2,
            'maxContentLength': defaultToConfig2,
            'maxBodyLength': defaultToConfig2,
            'beforeRedirect': defaultToConfig2,
            'transport': defaultToConfig2,
            'httpAgent': defaultToConfig2,
            'httpsAgent': defaultToConfig2,
            'cancelToken': defaultToConfig2,
            'socketPath': defaultToConfig2,
            'responseEncoding': defaultToConfig2,
            'validateStatus': mergeDirectKeys
        };

        utils.forEach(Object.keys(config1).concat(Object.keys(config2)), function computeConfigValue(prop) {
            var merge = mergeMap[prop] || mergeDeepProperties;
            var configValue = merge(prop);
            (utils.isUndefined(configValue) && merge !== mergeDirectKeys) || (config[prop] = configValue);
        });

        return config;
    };

    var data = {
        "version": "0.27.2"
    };

    var VERSION = data.version;


    var validators$1 = {};

    // eslint-disable-next-line func-names
    ['object', 'boolean', 'number', 'function', 'string', 'symbol'].forEach(function (type, i) {
        validators$1[type] = function validator(thing) {
            return typeof thing === type || 'a' + (i < 1 ? 'n ' : ' ') + type;
        };
    });

    var deprecatedWarnings = {};

    /**
     * Transitional option validator
     * @param {function|boolean?} validator - set to false if the transitional option has been removed
     * @param {string?} version - deprecated version / removed since version
     * @param {string?} message - some message with additional info
     * @returns {function}
     */
    validators$1.transitional = function transitional(validator, version, message) {
        function formatMessage(opt, desc) {
            return '[Axios v' + VERSION + '] Transitional option \'' + opt + '\'' + desc + (message ? '. ' + message : '');
        }

        // eslint-disable-next-line func-names
        return function (value, opt, opts) {
            if (validator === false) {
                throw new AxiosError_1(
                    formatMessage(opt, ' has been removed' + (version ? ' in ' + version : '')),
                    AxiosError_1.ERR_DEPRECATED
                );
            }

            if (version && !deprecatedWarnings[opt]) {
                deprecatedWarnings[opt] = true;
                // eslint-disable-next-line no-console
                console.warn(
                    formatMessage(
                        opt,
                        ' has been deprecated since v' + version + ' and will be removed in the near future'
                    )
                );
            }

            return validator ? validator(value, opt, opts) : true;
        };
    };

    /**
     * Assert object's properties type
     * @param {object} options
     * @param {object} schema
     * @param {boolean?} allowUnknown
     */

    function assertOptions(options, schema, allowUnknown) {
        if (typeof options !== 'object') {
            throw new AxiosError_1('options must be an object', AxiosError_1.ERR_BAD_OPTION_VALUE);
        }
        var keys = Object.keys(options);
        var i = keys.length;
        while (i-- > 0) {
            var opt = keys[i];
            var validator = schema[opt];
            if (validator) {
                var value = options[opt];
                var result = value === undefined || validator(value, opt, options);
                if (result !== true) {
                    throw new AxiosError_1('option ' + opt + ' must be ' + result, AxiosError_1.ERR_BAD_OPTION_VALUE);
                }
                continue;
            }
            if (allowUnknown !== true) {
                throw new AxiosError_1('Unknown option ' + opt, AxiosError_1.ERR_BAD_OPTION);
            }
        }
    }

    var validator = {
        assertOptions: assertOptions,
        validators: validators$1
    };

    var validators = validator.validators;

    /**
     * Create a new instance of Axios
     *
     * @param {Object} instanceConfig The default config for the instance
     */
    function Axios(instanceConfig) {
        this.defaults = instanceConfig;
        this.interceptors = {
            request: new InterceptorManager_1(),
            response: new InterceptorManager_1()
        };
    }

    /**
     * Dispatch a request
     *
     * @param {Object} config The config specific for this request (merged with this.defaults)
     */
    Axios.prototype.request = function request(configOrUrl, config) {
        /*eslint no-param-reassign:0*/
        // Allow for axios('example/url'[, config]) a la fetch API
        if (typeof configOrUrl === 'string') {
            config = config || {};
            config.url = configOrUrl;
        } else {
            config = configOrUrl || {};
        }

        config = mergeConfig(this.defaults, config);

        // Set config.method
        if (config.method) {
            config.method = config.method.toLowerCase();
        } else if (this.defaults.method) {
            config.method = this.defaults.method.toLowerCase();
        } else {
            config.method = 'get';
        }

        var transitional = config.transitional;

        if (transitional !== undefined) {
            validator.assertOptions(transitional, {
                silentJSONParsing: validators.transitional(validators.boolean),
                forcedJSONParsing: validators.transitional(validators.boolean),
                clarifyTimeoutError: validators.transitional(validators.boolean)
            }, false);
        }

        // filter out skipped interceptors
        var requestInterceptorChain = [];
        var synchronousRequestInterceptors = true;
        this.interceptors.request.forEach(function unshiftRequestInterceptors(interceptor) {
            if (typeof interceptor.runWhen === 'function' && interceptor.runWhen(config) === false) {
                return;
            }

            synchronousRequestInterceptors = synchronousRequestInterceptors && interceptor.synchronous;

            requestInterceptorChain.unshift(interceptor.fulfilled, interceptor.rejected);
        });

        var responseInterceptorChain = [];
        this.interceptors.response.forEach(function pushResponseInterceptors(interceptor) {
            responseInterceptorChain.push(interceptor.fulfilled, interceptor.rejected);
        });

        var promise;

        if (!synchronousRequestInterceptors) {
            var chain = [dispatchRequest, undefined];

            Array.prototype.unshift.apply(chain, requestInterceptorChain);
            chain = chain.concat(responseInterceptorChain);

            promise = Promise.resolve(config);
            while (chain.length) {
                promise = promise.then(chain.shift(), chain.shift());
            }

            return promise;
        }


        var newConfig = config;
        while (requestInterceptorChain.length) {
            var onFulfilled = requestInterceptorChain.shift();
            var onRejected = requestInterceptorChain.shift();
            try {
                newConfig = onFulfilled(newConfig);
            } catch (error) {
                onRejected(error);
                break;
            }
        }

        try {
            promise = dispatchRequest(newConfig);
        } catch (error) {
            return Promise.reject(error);
        }

        while (responseInterceptorChain.length) {
            promise = promise.then(responseInterceptorChain.shift(), responseInterceptorChain.shift());
        }

        return promise;
    };

    Axios.prototype.getUri = function getUri(config) {
        config = mergeConfig(this.defaults, config);
        var fullPath = buildFullPath(config.baseURL, config.url);
        return buildURL(fullPath, config.params, config.paramsSerializer);
    };

    // Provide aliases for supported request methods
    utils.forEach(['delete', 'get', 'head', 'options'], function forEachMethodNoData(method) {
        /*eslint func-names:0*/
        Axios.prototype[method] = function (url, config) {
            return this.request(mergeConfig(config || {}, {
                method: method,
                url: url,
                data: (config || {}).data
            }));
        };
    });

    utils.forEach(['post', 'put', 'patch'], function forEachMethodWithData(method) {
        /*eslint func-names:0*/

        function generateHTTPMethod(isForm) {
            return function httpMethod(url, data, config) {
                return this.request(mergeConfig(config || {}, {
                    method: method,
                    headers: isForm ? {
                        'Content-Type': 'multipart/form-data'
                    } : {},
                    url: url,
                    data: data
                }));
            };
        }

        Axios.prototype[method] = generateHTTPMethod();

        Axios.prototype[method + 'Form'] = generateHTTPMethod(true);
    });

    var Axios_1 = Axios;

    /**
     * A `CancelToken` is an object that can be used to request cancellation of an operation.
     *
     * @class
     * @param {Function} executor The executor function.
     */
    function CancelToken(executor) {
        if (typeof executor !== 'function') {
            throw new TypeError('executor must be a function.');
        }

        var resolvePromise;

        this.promise = new Promise(function promiseExecutor(resolve) {
            resolvePromise = resolve;
        });

        var token = this;

        // eslint-disable-next-line func-names
        this.promise.then(function (cancel) {
            if (!token._listeners) return;

            var i;
            var l = token._listeners.length;

            for (i = 0; i < l; i++) {
                token._listeners[i](cancel);
            }
            token._listeners = null;
        });

        // eslint-disable-next-line func-names
        this.promise.then = function (onfulfilled) {
            var _resolve;
            // eslint-disable-next-line func-names
            var promise = new Promise(function (resolve) {
                token.subscribe(resolve);
                _resolve = resolve;
            }).then(onfulfilled);

            promise.cancel = function reject() {
                token.unsubscribe(_resolve);
            };

            return promise;
        };

        executor(function cancel(message) {
            if (token.reason) {
                // Cancellation has already been requested
                return;
            }

            token.reason = new CanceledError_1(message);
            resolvePromise(token.reason);
        });
    }

    /**
     * Throws a `CanceledError` if cancellation has been requested.
     */
    CancelToken.prototype.throwIfRequested = function throwIfRequested() {
        if (this.reason) {
            throw this.reason;
        }
    };

    /**
     * Subscribe to the cancel signal
     */

    CancelToken.prototype.subscribe = function subscribe(listener) {
        if (this.reason) {
            listener(this.reason);
            return;
        }

        if (this._listeners) {
            this._listeners.push(listener);
        } else {
            this._listeners = [listener];
        }
    };

    /**
     * Unsubscribe from the cancel signal
     */

    CancelToken.prototype.unsubscribe = function unsubscribe(listener) {
        if (!this._listeners) {
            return;
        }
        var index = this._listeners.indexOf(listener);
        if (index !== -1) {
            this._listeners.splice(index, 1);
        }
    };

    /**
     * Returns an object that contains a new `CancelToken` and a function that, when called,
     * cancels the `CancelToken`.
     */
    CancelToken.source = function source() {
        var cancel;
        var token = new CancelToken(function executor(c) {
            cancel = c;
        });
        return {
            token: token,
            cancel: cancel
        };
    };

    var CancelToken_1 = CancelToken;

    /**
     * Syntactic sugar for invoking a function and expanding an array for arguments.
     *
     * Common use case would be to use `Function.prototype.apply`.
     *
     *  ```js
     *  function f(x, y, z) {}
     *  var args = [1, 2, 3];
     *  f.apply(null, args);
     *  ```
     *
     * With `spread` this example can be re-written.
     *
     *  ```js
     *  spread(function(x, y, z) {})([1, 2, 3]);
     *  ```
     *
     * @param {Function} callback
     * @returns {Function}
     */
    var spread = function spread(callback) {
        return function wrap(arr) {
            return callback.apply(null, arr);
        };
    };

    /**
     * Determines whether the payload is an error thrown by Axios
     *
     * @param {*} payload The value to test
     * @returns {boolean} True if the payload is an error thrown by Axios, otherwise false
     */
    var isAxiosError = function isAxiosError(payload) {
        return utils.isObject(payload) && (payload.isAxiosError === true);
    };

    /**
     * Create an instance of Axios
     *
     * @param {Object} defaultConfig The default config for the instance
     * @return {Axios} A new instance of Axios
     */
    function createInstance(defaultConfig) {
        var context = new Axios_1(defaultConfig);
        var instance = bind(Axios_1.prototype.request, context);

        // Copy axios.prototype to instance
        utils.extend(instance, Axios_1.prototype, context);

        // Copy context to instance
        utils.extend(instance, context);

        // Factory for creating new instances
        instance.create = function create(instanceConfig) {
            return createInstance(mergeConfig(defaultConfig, instanceConfig));
        };

        return instance;
    }

    // Create the default instance to be exported
    var axios$1 = createInstance(defaults_1);

    // Expose Axios class to allow class inheritance
    axios$1.Axios = Axios_1;

    // Expose Cancel & CancelToken
    axios$1.CanceledError = CanceledError_1;
    axios$1.CancelToken = CancelToken_1;
    axios$1.isCancel = isCancel;
    axios$1.VERSION = data.version;
    axios$1.toFormData = toFormData_1;

    // Expose AxiosError class
    axios$1.AxiosError = AxiosError_1;

    // alias for CanceledError for backward compatibility
    axios$1.Cancel = axios$1.CanceledError;

    // Expose all/spread
    axios$1.all = function all(promises) {
        return Promise.all(promises);
    };
    axios$1.spread = spread;

    // Expose isAxiosError
    axios$1.isAxiosError = isAxiosError;

    var axios_1 = axios$1;

    // Allow use of default import syntax in TypeScript
    var _default = axios$1;
    axios_1.default = _default;

    var axios = axios_1;

    class RTCEndpoint extends Event$1 {
        constructor(options) {
            super('RTCPusherPlayer');
            this.TAG = '[RTCPusherPlayer]';
            let defaults = {
                element: '',
                // html video element
                debug: false,
                // if output debug log
                zlmsdpUrl: '',
                simulcast: false,
                useCamera: true,
                audioEnable: true,
                videoEnable: true,
                recvOnly: false,
                resolution: {
                    w: 0,
                    h: 0
                },
                usedatachannel: false
            };
            this.options = Object.assign({}, defaults, options);
            if (this.options.debug) {
                setLogger();
            }
            this.e = {
                onicecandidate: this._onIceCandidate.bind(this),
                ontrack: this._onTrack.bind(this),
                onicecandidateerror: this._onIceCandidateError.bind(this),
                onconnectionstatechange: this._onconnectionstatechange.bind(this),
                ondatachannelopen: this._onDataChannelOpen.bind(this),
                ondatachannelmsg: this._onDataChannelMsg.bind(this),
                ondatachannelerr: this._onDataChannelErr.bind(this),
                ondatachannelclose: this._onDataChannelClose.bind(this)
            };
            this._remoteStream = null;
            this._localStream = null;
            this._tracks = [];
            this.pc = new RTCPeerConnection(null);
            this.pc.onicecandidate = this.e.onicecandidate;
            this.pc.onicecandidateerror = this.e.onicecandidateerror;
            this.pc.ontrack = this.e.ontrack;
            this.pc.onconnectionstatechange = this.e.onconnectionstatechange;
            this.datachannel = null;
            if (this.options.usedatachannel) {
                this.datachannel = this.pc.createDataChannel('chat');
                this.datachannel.onclose = this.e.ondatachannelclose;
                this.datachannel.onerror = this.e.ondatachannelerr;
                this.datachannel.onmessage = this.e.ondatachannelmsg;
                this.datachannel.onopen = this.e.ondatachannelopen;
            }
            if (!this.options.recvOnly && (this.options.audioEnable || this.options.videoEnable)) this.start(); else this.receive();
        }

        receive() {

            //debug.error(this.TAG,'this not implement');
            const AudioTransceiverInit = {
                direction: 'recvonly',
                sendEncodings: []
            };
            const VideoTransceiverInit = {
                direction: 'recvonly',
                sendEncodings: []
            };
            if (this.options.videoEnable) {
                this.pc.addTransceiver('video', VideoTransceiverInit);
            }
            if (this.options.audioEnable) {
                this.pc.addTransceiver('audio', AudioTransceiverInit);
            }
            this.pc.createOffer().then(desc => {
                log(this.TAG, 'offer:', desc.sdp);
                this.pc.setLocalDescription(desc).then(() => {
                    axios({
                        method: 'post',
                        url: this.options.zlmsdpUrl,
                        responseType: 'json',
                        data: desc.sdp,
                        headers: {
                            'Content-Type': 'text/plain;charset=utf-8'
                        }
                    }).then(response => {
                        let ret = response.data; //JSON.parse(response.data);
                        if (ret.code != 0) {
                            // mean failed for offer/anwser exchange
                            this.dispatch(Events$1.WEBRTC_OFFER_ANWSER_EXCHANGE_FAILED, ret);
                            return;
                        }
                        let anwser = {};
                        anwser.sdp = ret.sdp;
                        anwser.type = 'answer';
                        log(this.TAG, 'answer:', ret.sdp);
                        this.pc.setRemoteDescription(anwser).then(() => {
                            log(this.TAG, 'set remote sucess');
                        }).catch(e => {
                            error(this.TAG, e);
                        });
                    });
                });
            }).catch(e => {
                error(this.TAG, e);
            });
        }

        start() {
            let videoConstraints = false;
            let audioConstraints = false;
            if (this.options.useCamera) {
                if (this.options.videoEnable) videoConstraints = new VideoTrackConstraints(VideoSourceInfo.CAMERA);
                if (this.options.audioEnable) audioConstraints = new AudioTrackConstraints(AudioSourceInfo.MIC);
            } else {
                if (this.options.videoEnable) {
                    videoConstraints = new VideoTrackConstraints(VideoSourceInfo.SCREENCAST);
                    if (this.options.audioEnable) audioConstraints = new AudioTrackConstraints(AudioSourceInfo.SCREENCAST);
                } else {
                    if (this.options.audioEnable) audioConstraints = new AudioTrackConstraints(AudioSourceInfo.MIC); else {
                        // error shared display media not only audio
                        error(this.TAG, 'error paramter');
                    }
                }
            }
            if (this.options.resolution.w != 0 && this.options.resolution.h != 0 && typeof videoConstraints == 'object') {
                videoConstraints.resolution = new Resolution(this.options.resolution.w, this.options.resolution.h);
            }
            MediaStreamFactory.createMediaStream(new StreamConstraints(audioConstraints, videoConstraints)).then(stream => {
                this._localStream = stream;
                this.dispatch(Events$1.WEBRTC_ON_LOCAL_STREAM, stream);
                const AudioTransceiverInit = {
                    direction: 'sendrecv',
                    sendEncodings: []
                };
                const VideoTransceiverInit = {
                    direction: 'sendrecv',
                    sendEncodings: []
                };
                if (this.options.simulcast && stream.getVideoTracks().length > 0) {
                    VideoTransceiverInit.sendEncodings = [{
                        rid: 'h',
                        active: true,
                        maxBitrate: 1000000
                    }, {
                        rid: 'm',
                        active: true,
                        maxBitrate: 500000,
                        scaleResolutionDownBy: 2
                    }, {
                        rid: 'l',
                        active: true,
                        maxBitrate: 200000,
                        scaleResolutionDownBy: 4
                    }];
                }
                if (this.options.audioEnable) {
                    if (stream.getAudioTracks().length > 0) {
                        this.pc.addTransceiver(stream.getAudioTracks()[0], AudioTransceiverInit);
                    } else {
                        AudioTransceiverInit.direction = 'recvonly';
                        this.pc.addTransceiver('audio', AudioTransceiverInit);
                    }
                }
                if (this.options.videoEnable) {
                    if (stream.getVideoTracks().length > 0) {
                        this.pc.addTransceiver(stream.getVideoTracks()[0], VideoTransceiverInit);
                    } else {
                        VideoTransceiverInit.direction = 'recvonly';
                        this.pc.addTransceiver('video', VideoTransceiverInit);
                    }
                }

                /*
	      stream.getTracks().forEach((track,idx)=>{
	          debug.log(this.TAG,track);
	          this.pc.addTrack(track);
	      });
	      */
                this.pc.createOffer().then(desc => {
                    log(this.TAG, 'offer:', desc.sdp);
                    this.pc.setLocalDescription(desc).then(() => {
                        axios({
                            method: 'post',
                            url: this.options.zlmsdpUrl,
                            responseType: 'json',
                            data: desc.sdp,
                            headers: {
                                'Content-Type': 'text/plain;charset=utf-8'
                            }
                        }).then(response => {
                            let ret = response.data; //JSON.parse(response.data);
                            if (ret.code != 0) {
                                // mean failed for offer/anwser exchange
                                this.dispatch(Events$1.WEBRTC_OFFER_ANWSER_EXCHANGE_FAILED, ret);
                                return;
                            }
                            let anwser = {};
                            anwser.sdp = ret.sdp;
                            anwser.type = 'answer';
                            log(this.TAG, 'answer:', ret.sdp);
                            this.pc.setRemoteDescription(anwser).then(() => {
                                log(this.TAG, 'set remote sucess');
                            }).catch(e => {
                                error(this.TAG, e);
                            });
                        });
                    });
                }).catch(e => {
                    error(this.TAG, e);
                });
            }).catch(e => {
                this.dispatch(Events$1.CAPTURE_STREAM_FAILED);
                //debug.error(this.TAG,e);
            });

            //const offerOptions = {};
            /*
	    if (typeof this.pc.addTransceiver === 'function') {
	        // |direction| seems not working on Safari.
	        this.pc.addTransceiver('audio', { direction: 'recvonly' });
	        this.pc.addTransceiver('video', { direction: 'recvonly' });
	    } else {
	        offerOptions.offerToReceiveAudio = true;
	        offerOptions.offerToReceiveVideo = true;
	    }
	    */
        }

        _onIceCandidate(event) {
            if (event.candidate) {
                log(this.TAG, 'Remote ICE candidate: \n ' + event.candidate.candidate);
                // Send the candidate to the remote peer
            }
        }

        _onTrack(event) {
            this._tracks.push(event.track);
            if (this.options.element && event.streams && event.streams.length > 0) {
                this.options.element.srcObject = event.streams[0];
                this._remoteStream = event.streams[0];
                this.dispatch(Events$1.WEBRTC_ON_REMOTE_STREAMS, event);
            } else {
                if (this.pc.getReceivers().length == this._tracks.length) {
                    log(this.TAG, 'play remote stream ');
                    this._remoteStream = new MediaStream(this._tracks);
                    this.options.element.srcObject = this._remoteStream;
                } else {
                    error(this.TAG, 'wait stream track finish');
                }
            }
        }

        _onIceCandidateError(event) {
            this.dispatch(Events$1.WEBRTC_ICE_CANDIDATE_ERROR, event);
        }

        _onconnectionstatechange(event) {
            this.dispatch(Events$1.WEBRTC_ON_CONNECTION_STATE_CHANGE, this.pc.connectionState);
        }

        _onDataChannelOpen(event) {
            log(this.TAG, 'ondatachannel open:', event);
            this.dispatch(Events$1.WEBRTC_ON_DATA_CHANNEL_OPEN, event);
        }

        _onDataChannelMsg(event) {
            log(this.TAG, 'ondatachannel msg:', event);
            this.dispatch(Events$1.WEBRTC_ON_DATA_CHANNEL_MSG, event);
        }

        _onDataChannelErr(event) {
            log(this.TAG, 'ondatachannel err:', event);
            this.dispatch(Events$1.WEBRTC_ON_DATA_CHANNEL_ERR, event);
        }

        _onDataChannelClose(event) {
            log(this.TAG, 'ondatachannel close:', event);
            this.dispatch(Events$1.WEBRTC_ON_DATA_CHANNEL_CLOSE, event);
        }

        sendMsg(data) {
            if (this.datachannel != null) {
                this.datachannel.send(data);
            } else {
                error(this.TAG, 'data channel is null');
            }
        }

        closeDataChannel() {
            if (this.datachannel) {
                this.datachannel.close();
                this.datachannel = null;
            }
        }

        close() {
            this.closeDataChannel();
            if (this.pc) {
                this.pc.close();
                this.pc = null;
            }
            if (this.options) {
                this.options = null;
            }
            if (this._localStream) {
                this._localStream.getTracks().forEach((track, idx) => {
                    track.stop();
                });
            }
            if (this._remoteStream) {
                this._remoteStream.getTracks().forEach((track, idx) => {
                    track.stop();
                });
            }
            this._tracks.forEach((track, idx) => {
                track.stop();
            });
            this._tracks = [];
        }

        get remoteStream() {
            return this._remoteStream;
        }

        get localStream() {
            return this._localStream;
        }
    }

    const quickScan = [{
        'label': '4K(UHD)',
        'width': 3840,
        'height': 2160
    }, {
        'label': '1080p(FHD)',
        'width': 1920,
        'height': 1080
    }, {
        'label': 'UXGA',
        'width': 1600,
        'height': 1200,
        'ratio': '4:3'
    }, {
        'label': '720p(HD)',
        'width': 1280,
        'height': 720
    }, {
        'label': 'SVGA',
        'width': 800,
        'height': 600
    }, {
        'label': 'VGA',
        'width': 640,
        'height': 480
    }, {
        'label': '360p(nHD)',
        'width': 640,
        'height': 360
    }, {
        'label': 'CIF',
        'width': 352,
        'height': 288
    }, {
        'label': 'QVGA',
        'width': 320,
        'height': 240
    }, {
        'label': 'QCIF',
        'width': 176,
        'height': 144
    }, {
        'label': 'QQVGA',
        'width': 160,
        'height': 120
    }];

    function GetSupportCameraResolutions$1() {
        return new Promise(function (resolve, reject) {
            let resolutions = [];
            let ok = 0;
            let err = 0;
            for (let i = 0; i < quickScan.length; ++i) {
                let videoConstraints = new VideoTrackConstraints(VideoSourceInfo.CAMERA);
                videoConstraints.resolution = new Resolution(quickScan[i].width, quickScan[i].height);
                MediaStreamFactory.createMediaStream(new StreamConstraints(false, videoConstraints)).then(stream => {
                    resolutions.push(quickScan[i]);
                    ok++;
                    if (ok + err == quickScan.length) {
                        resolve(resolutions);
                    }
                }).catch(e => {
                    err++;
                    if (ok + err == quickScan.length) {
                        resolve(resolutions);
                    }
                });
            }
        });
    }

    function GetAllScanResolution$1() {
        return quickScan;
    }

    function isSupportResolution$1(w, h) {
        return new Promise(function (resolve, reject) {
            let videoConstraints = new VideoTrackConstraints(VideoSourceInfo.CAMERA);
            videoConstraints.resolution = new Resolution(w, h);
            MediaStreamFactory.createMediaStream(new StreamConstraints(false, videoConstraints)).then(stream => {
                resolve();
            }).catch(e => {
                reject(e);
            });
        });
    }

    console.log('build date:', BUILD_DATE);
    console.log('version:', VERSION$1);
    const Events = Events$1;
    const Media = media;
    const Endpoint = RTCEndpoint;
    const GetSupportCameraResolutions = GetSupportCameraResolutions$1;
    const GetAllScanResolution = GetAllScanResolution$1;
    const isSupportResolution = isSupportResolution$1;

    exports.Endpoint = Endpoint;
    exports.Events = Events;
    exports.GetAllScanResolution = GetAllScanResolution;
    exports.GetSupportCameraResolutions = GetSupportCameraResolutions;
    exports.Media = Media;
    exports.isSupportResolution = isSupportResolution;

    Object.defineProperty(exports, '__esModule', {value: true});

    return exports;

})({});
//# sourceMappingURL=ZLMRTCClient.js.map

export {
    ZLMRTCClient
}
